A338062 Numbers k such that the Enots Wolley sequence A336957(k) is odd.

1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25, 28, 29, 32, 33, 36, 37, 40, 41, 44, 45, 48, 49, 52, 53, 56, 57, 60, 61, 64, 65, 68, 69, 72, 73, 76, 77, 80, 81, 84, 85, 88, 89, 92, 93, 96, 97, 100, 101, 104, 105, 108, 109, 112, 113, 116, 117, 120, 121, 124, 125, 128, 129, 132, 133, 136, 137

Offset

1,2

Comments

a(n) = A042948(n) for n<=1065, but then the two sequences start to differ. - R. J. Mathar, Nov 06 2020

Links

N. J. A. Sloane, Table of n, a(n) for n = 1..20000

Mathematica

M = 1000;
A[1] = 1; A[2] = 2;
Clear[B]; B[_] = 0;
For[n = 3, True, n++, For[k = 3, k <= M, k++, If[B[k] == 0 && GCD[k, A[n-1]] > 1 && GCD[k, A[n-2]] == 1, If[Length[FactorInteger[k][[All, 1]] ~Complement~ FactorInteger[A[n-1]][[All, 1]]] > 0, A[n] = k; B[k] = 1; Break[]]]]; If[k > M, Break[]]];
Reap[For[k = 1, k <= M, k++, If[OddQ[A[k]], Sow[k]]]][[2, 1]] (* Jean-François Alcover, Oct 23 2020, after Maple code in A336957 *)

Crossrefs

Cf. A336957, A338063-A338069.

Sequence in context: A285260 A190671 A042948 * A126001 A321333 A333384

Adjacent sequences: A338059 A338060 A338061 * A338063 A338064 A338065

Keyword

nonn

Author

N. J. A. Sloane, Oct 18 2020

Status

approved