A253049 Numbers in A098550 which appear immediately after a prime.

3, 4, 6, 10, 13, 33, 18, 42, 48, 31, 58, 70, 43, 82, 90, 102, 110, 120, 126, 140, 144, 154, 150, 182, 180, 198, 200, 220, 216, 228, 272, 252, 280, 270, 300, 306, 312, 330, 336, 340, 348, 360, 390, 392, 396, 400, 442, 438, 468, 440, 506, 480, 484, 500, 486, 518, 528, 540, 574, 546, 570, 572, 616

Offset

1,1

Comments

It is conjectured that this is the same as A253048 except for the addition of 3, 13, 31, and 43 (the upper members of the twin primes in A098550).

a(n) = A098550(A251239(n)+1). - Reinhard Zumkeller, Dec 29 2014

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

David L. Applegate, Hans Havermann, Bob Selcoe, Vladimir Shevelev, N. J. A. Sloane, and Reinhard Zumkeller, The Yellowstone Permutation, arXiv preprint arXiv:1501.01669, 2015 and J. Int. Seq. 18 (2015) 15.6.7.

Mathematica

f[lst_] := Block[{k = 4}, While[GCD[lst[[-2]], k] == 1 || GCD[lst[[-1]], k] > 1 || MemberQ[lst, k], k++]; Append[lst, k]];
A098550 = Nest[f, {1, 2, 3}, 1000];
sp = SequencePosition[A098550, {_?PrimeQ, _}] [[All, 2]];
A098550[[sp]] (* Jean-François Alcover, Sep 03 2018, after Robert G. Wilson v in A098550 *)

Crossrefs

Cf. A098550. See A253048 for another version.

Cf. A251239.

Sequence in context: A240577 A365614 A074321 * A167410 A302340 A310003

Adjacent sequences: A253046 A253047 A253048 * A253050 A253051 A253052

Keyword

nonn

Author

N. J. A. Sloane, Dec 27 2014

Status

approved