A271233 Composite integers sandwiched between primes p, q with q-p = 8.

90, 91, 92, 93, 94, 95, 96, 360, 361, 362, 363, 364, 365, 366, 390, 391, 392, 393, 394, 395, 396, 402, 403, 404, 405, 406, 407, 408, 450, 451, 452, 453, 454, 455, 456, 480, 481, 482, 483, 484, 485, 486, 492, 493, 494, 495, 496, 497, 498, 684, 685, 686, 687, 688, 689, 690

Offset

1,1

Links

Table of n, a(n) for n=1..56.

Laurent Coppey, Décompositions multiplicatives directes des entiers, Diagrammes, 65-66 (2011), p. 1-68, in French, see J8 p. 11.

Example

The composite number 90 is sandwiched between consecutive primes 89 and 97, and 97-89=8, so 90 is a member of the sequence.

Mathematica

Range[#[[1]]+1, #[[2]]-1]&/@Select[Partition[Prime[Range[150]], 2, 1], #[[2]]-#[[1]] == 8&]//Flatten (* Harvey P. Dale, May 15 2022 *)

Prog

(PARI) lista(nn) = {forcomposite(c=4, nn, if ((p=precprime(c)) && ((nextprime(c)-p)==8), print1(c, ", ")); ); }

Crossrefs

Cf. A014574, A031926, A045881, A271211, A271232.

Sequence in context: A161823 A270173 A003899 * A050652 A025377 A257445

Adjacent sequences: A271230 A271231 A271232 * A271234 A271235 A271236

Keyword

nonn

Author

Michel Marcus, Apr 02 2016

Status

approved