OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
Laurent Coppey, Décompositions multiplicatives directes des entiers, Diagrammes, 65-66 (2011), p. 1-68, in French, see J4 p. 11.
EXAMPLE
The composite number 8 is sandwiched between primes 7 and 11, and 11-7=4, so 8 is a member of the sequence.
MATHEMATICA
Range[#[[1]]+1, #[[2]]-1]&/@Select[Partition[Prime[Range[100]], 2, 1], #[[2]]- #[[1]] == 4&]//Flatten (* Harvey P. Dale, Oct 12 2019 *)
PROG
(PARI) lista(nn) = {forcomposite(c=4, nn, if ((p=precprime(c)) && ((nextprime(c)-p)==4), print1(c, ", ")); ); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Apr 02 2016
STATUS
approved