The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A282808

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a(1)=3; for n>=2, a(n) is the smallest m>a(n-1) such that odd part of a(1) + ... + a(n-1) + m is prime.
(history; published version)

#8 by Charles R Greathouse IV at Wed Feb 22 03:47:18 EST 2017

STATUS

editing

approved

#7 by Charles R Greathouse IV at Wed Feb 22 03:47:08 EST 2017

LINKS

Charles R Greathouse IV, <a href="/A282808/b282808.txt">Table of n, a(n) for n = 1..10000</a>

PROG

(PARI) oddpart(n)=n>>valuation(n, 2)

first(n)=my(v=vector(n), s, m); v[1]=s=3; for(k=2, n, m=v[k-1]; while(!isprime(oddpart(m+++s)), ); s+=m; v[k]=m); v \\ Charles R Greathouse IV, Feb 22 2017

STATUS

proposed

editing

#6 by Giovanni Resta at Tue Feb 21 10:14:57 EST 2017

STATUS

editing

proposed

#5 by Giovanni Resta at Tue Feb 21 10:14:53 EST 2017

MATHEMATICA

a[1]=3; s[1]=3; s[n_] := s[n-1]+a[n]; a[n_]:=a[n]=Block[{m, u}, For[m = a[n-1] + 1, u = s[n-1] + m; ! PrimeQ[ u/ 2^IntegerExponent[u, 2]], m++]; m]; Array[a, 62] (* Giovanni Resta, Feb 21 2017 *)

STATUS

proposed

editing

#4 by Vladimir Shevelev at Tue Feb 21 10:05:35 EST 2017

STATUS

editing

proposed

#3 by Vladimir Shevelev at Tue Feb 21 10:05:22 EST 2017

EXTENSIONS

More terms from Peter J. C. Moses, Feb 21 2017

#2 by Vladimir Shevelev at Tue Feb 21 10:03:04 EST 2017

NAME

allocated a(1)=3; for Vladimir Shevelevn>=2, a(n) is the smallest m>a(n-1) such that odd part of a(1) + ... + a(n-1) + m is prime.

DATA

3, 4, 5, 7, 9, 10, 14, 15, 16, 18, 21, 24, 26, 27, 28, 30, 35, 36, 39, 42, 43, 44, 45, 46, 47, 49, 50, 54, 55, 56, 58, 60, 66, 69, 72, 74, 76, 78, 80, 82, 83, 87, 88, 93, 98, 99, 103, 104, 105, 106, 108, 110, 111, 114, 115, 116, 118, 120, 122, 123, 126, 127

OFFSET

1,1

COMMENTS

The corresponding primes are 3,7,3,19,7,19,13,67,83,101,61,73,...

CROSSREFS

Cf. A000040, A000265.

KEYWORD

allocated

nonn

AUTHOR

Vladimir Shevelev, Feb 21 2017

STATUS

approved

editing

#1 by Vladimir Shevelev at Tue Feb 21 10:03:04 EST 2017

NAME

allocated for Vladimir Shevelev

KEYWORD

allocated

STATUS

approved