A340086 - OEIS

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A340086 - OEIS

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A340086

a(1) = 0, for n > 1, a(n) = A000265(n-1) / gcd(n-1, A336466(n)).

4

0, 1, 1, 3, 1, 5, 1, 7, 1, 9, 1, 11, 1, 13, 7, 15, 1, 17, 1, 19, 5, 21, 1, 23, 3, 25, 13, 9, 1, 29, 1, 31, 1, 33, 17, 35, 1, 37, 19, 39, 1, 41, 1, 43, 11, 45, 1, 47, 1, 49, 25, 17, 1, 53, 27, 55, 7, 57, 1, 59, 1, 61, 31, 63, 1, 13, 1, 67, 17, 23, 1, 71, 1, 73, 37, 25, 19, 77, 1, 79, 5, 81, 1, 83, 21, 85, 43, 87, 1, 89

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

COMMENTS

From the second term onward, the odd part of A340083.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..8191

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

FORMULA

a(1) = 0; for n > 1, a(n) = A000265(n-1) / A340084(n) = A000265(A340083(n)).

PROG

(PARI)

A000265(n) = (n>>valuation(n, 2));

A336466(n) = { my(f=factor(n)); prod(k=1, #f~, if(2==f[k, 1], 1, (A000265(f[k, 1]-1))^f[k, 2])); };

A340086(n) = if(1==n, 0, my(u=A336466(n)); A000265(n-1)/gcd(n-1, u));

CROSSREFS

Cf. A000265, A003958, A003961, A019565, A336466, A339901, A340083, A340084, A340085.

Cf. also A160596.

Sequence in context: A327514 A009001 A093178 * A307153 A339421 A336898

Adjacent sequences: A340083 A340084 A340085 * A340087 A340088 A340089

KEYWORD

nonn

AUTHOR

Antti Karttunen, Dec 29 2020

STATUS

approved