OFFSET
1,1
COMMENTS
Prime gaps (A001223) are the differences between consecutive prime numbers. They begin: 1, 2, 2, 4, 2, 4, 2, 4, 6, ...
MATHEMATICA
nn=1000;
gaps=Differences[Array[Prime, nn]];
mnrm[s_]:=If[Min@@s==1, mnrm[DeleteCases[s-1, 0]]+1, 0];
Table[Position[gaps, 2*n][[2, 1]], {n, mnrm[Select[Range[nn], Length[Position[gaps, 2*#]]>=2&]]}]
CROSSREFS
The position of the first (instead of second) appearance of 2n is A038664.
Column k = 2 of A356222.
The position of the n-th appearance of 2n is A356223.
A073491 lists numbers with gapless prime indices.
A274121 counts appearances of the n-th prime gap in those prior.
A356226 gives the lengths of maximal gapless intervals of prime indices.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Aug 02 2022
STATUS
approved