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Revision History for A309428

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Showing entries 1-10 | older changes
Irregular triangle read by rows: T(n,k) is the multiplicative order of {{A038566(n,k), 1}, {0, 1}} modulo n, n >= 1, 1 <= k <= A000010(n).
(history; published version)
#52 by Michael De Vlieger at Sat Feb 10 18:53:21 EST 2024
STATUS

proposed

approved

#51 by Michel Marcus at Sat Feb 10 17:24:52 EST 2024
STATUS

editing

proposed

#50 by Michel Marcus at Sat Feb 10 17:24:49 EST 2024
EXAMPLE

1,

2,

3, 2,

4, 2,

5, 4, 4, 2,

6, 2,

7, 3, 6, 3, 6, 2,

8, 4, 8, 2,

9, 6, 9, 6, 9, 2,

10, 4, 4, 2,

11, 10, 5, 5, 5, 10, 10, 10, 5, 2,

12, 4, 6, 2,

13, 12, 3, 6, 4, 12, 12, 4, 3, 6, 12, 2,

14, 6, 6, 6, 6, 2,

15, 4, 6, 12, 4, 10, 12, 2,

16, 8, 16, 4, 16, 8, 16, 2,

17, 8, 16, 4, 16, 16, 16, 8, 8, 16, 16, 16, 4, 16, 8, 2,

18, 6, 18, 6, 18, 2,

19, 18, 18, 9, 9, 9, 3, 6, 9, 18, 3, 6, 18, 18, 18, 9, 9, 2,

20, 4, 4, 4, 10, 4, 4, 2,

...

...

STATUS

proposed

editing

#49 by Jon E. Schoenfield at Sat Feb 10 17:11:31 EST 2024
STATUS

editing

proposed

#48 by Jon E. Schoenfield at Sat Feb 10 17:11:27 EST 2024
FORMULA

For gcd(n,r) = 1, 1 <= r <= n, let d(n,r) is be the multiplicative order of {{r, 1}, {0, 1}}, then T(n,k) = d(n,A038566(k)).

STATUS

approved

editing

#47 by Peter Luschny at Fri Sep 20 12:43:54 EDT 2019
STATUS

proposed

approved

#46 by Jianing Song at Thu Sep 19 05:07:25 EDT 2019
STATUS

editing

proposed

#45 by Jianing Song at Thu Sep 19 05:05:53 EDT 2019
COMMENTS

For Let M = {{r, 1}, {0, 1}}, then M^e = {{r^e, 1 + r + r^2 + ... + r^(e-1)}, {0, 1}}. As a result, for gcd(r, n) = 1, the multiplicative order of {{r, 1}, {0, 1}} modulo n is n if r == 1 (mod n) and ord(r,n*(r-1)) otherwise, where ord(r,t) is the multiplicative order of r modulo t.

FORMULA

For gcd(n,r) = 1, 1 <= r <= n, let d(n,r) is the multiplicative order of {{r, 1}, {0, 1}}, then T(n,k) = d(n,A038566(k)).

(a) If p is an odd prime, then d(p^e,r) = p^e if r == 1 (mod p), ord(r,p^e) otherwise;

(b) d(2^e,r) = 2^(e+1-v2(r+1)), where v2(t) is the 2-adic valuation of t;

(c) For gcd(m,n) = 1, d(m*n,r) = lcm(d(m,r mod m),d(n,r mod n)).

The LCM of the n-th row is A174824(n).

EXAMPLE

For n = 14 and k = 4, let M = {{A038566(n,k), 1}, {0, 1}} = {{9, 1}, {0, 1}}, then:

- M^2 mod 14 = {{11, 10}, {0, 1}};

- M^3 mod 14 = {{1, 7}, {0, 1}};

- M^4 mod 14 = {{9, 8}, {0, 1}};

- M^5 mod 14 = {{11, 3}, {0, 1}};

- M^6 mod 14 = {{1, 0}, {0, 1}}.

So T(14,4) = d(14,9) = 6.

PROG

(PARI) row(n) = my(v=vector(n, i, i), u=vector(eulerphi(n), i, n)); v=select(i->gcd(n, i)==1, v); for(i=2, #v, u[i]=znorder(Mod(v[i], n*(v[i]-1)))); u

CROSSREFS
#44 by Jianing Song at Wed Sep 18 19:35:27 EDT 2019
COMMENTS

For gcd(r, n) = 1, the multiplicative order of {{r, 1}, {0, 1}} modulo n is n if r == 1 (mod n) and ord(r,n*(r-1)) otherwise.

#43 by Jianing Song at Wed Sep 18 11:01:34 EDT 2019
NAME

allocated for Jianing SongIrregular triangle read by rows: T(n,k) is the multiplicative order of {{A038566(n,k), 1}, {0, 1}} modulo n, n >= 1, 1 <= k <= A000010(n).

DATA

1, 2, 3, 2, 4, 2, 5, 4, 4, 2, 6, 2, 7, 3, 6, 3, 6, 2, 8, 4, 8, 2, 9, 6, 9, 6, 9, 2, 10, 4, 4, 2, 11, 10, 5, 5, 5, 10, 10, 10, 5, 2, 12, 4, 6, 2, 13, 12, 3, 6, 4, 12, 12, 4, 3, 6, 12, 2, 14, 6, 6, 6, 6, 2, 15, 4, 6, 12, 4, 10, 12, 2, 16, 8, 16, 4, 16, 8, 16, 2, 17, 8, 16, 4, 16, 16, 16, 8

OFFSET

1,2

EXAMPLE

Table starts

1,

2,

3, 2,

4, 2,

5, 4, 4, 2,

6, 2,

7, 3, 6, 3, 6, 2,

8, 4, 8, 2,

9, 6, 9, 6, 9, 2,

10, 4, 4, 2,

11, 10, 5, 5, 5, 10, 10, 10, 5, 2,

12, 4, 6, 2,

13, 12, 3, 6, 4, 12, 12, 4, 3, 6, 12, 2,

14, 6, 6, 6, 6, 2,

15, 4, 6, 12, 4, 10, 12, 2,

16, 8, 16, 4, 16, 8, 16, 2,

17, 8, 16, 4, 16, 16, 16, 8, 8, 16, 16, 16, 4, 16, 8, 2,

18, 6, 18, 6, 18, 2,

19, 18, 18, 9, 9, 9, 3, 6, 9, 18, 3, 6, 18, 18, 18, 9, 9, 2,

20, 4, 4, 4, 10, 4, 4, 2,

...

KEYWORD

allocated

nonn,tabf

AUTHOR

Jianing Song, Sep 18 2019

STATUS

approved

editing