This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A258972 #18 Jun 20 2015 14:52:36 %S A258972 1,1,1,4,4,7,4,13,1,13,4,13,4,1,13,4,13,4,13,16,34,4,13,28,22,13,7,10, %T A258972 7,73,4,1,13,10,67,4,7,4,13,28,37,22,4,4,7,52,10,13,1,58,4,22,13,10, %U A258972 31,40,1,25,7,22,13,25,1,10,7,4,46,13,19,13,19,82,19,31,13,10,7,28,4,82,13,58,22,40,1,19,13,13,4,7,34,1 %N A258972 Number of other odd numbers between the twin primes, with a(1) = 1. %C A258972 Bisection of A256262. %F A258972 a(n) = abs((A001359(n+1) - A001359(n))/2 - 2). %F A258972 a(n) = abs((A006512(n+1) - A006512(n))/2 - 2). %e A258972 -------------------------------------------- %e A258972 . Other Twin %e A258972 . odd numbers primes %e A258972 n A255763 A001097 a(n) %e A258972 -------------------------------------------- %e A258972 1 1 3, 5, 7 1 %e A258972 2 9 11, 13 1 %e A258972 3 15 17, 19 1 %e A258972 4 21, 23, 25, 27 29, 31 4 %e A258972 5 33, 35, 37, 39 41, 43 4 %e A258972 ... %e A258972 For n = 5, between the successive pairs of twin primes [29, 31] and [41, 43] there are four odd numbers that are not twin primes: 33, 35, 37, 39, so a(5) = 4. %Y A258972 Cf. A001359, A001097, A006512, A255763, A256262. %K A258972 nonn %O A258972 1,4 %A A258972 _Omar E. Pol_, Jun 15 2015