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 A118480 #18 Mar 13 2023 11:51:45 %S A118480 0,1,1,2,3,2,2,3,3,5,6,5,6,2,7,5,6,8,7,7,7,12,10,10,11,11,12,10,10,12, %T A118480 11,13,10,10,10,10,9,8,7,9,3,4,4,4,11,13,15,17,19,19,22,19,16,13,17, %U A118480 16,15,16,14,17,16,21,24,19,19,13,17,17,19,19,16,11,13,13,22,19,19,17,22 %N A118480 (n-th 4k+1 prime minus n-th 4k+3 prime minus two)/4. %C A118480 Zero occurs infinitely often as do the negative numbers. %C A118480 First occurrence of a(n) beginning with 0: 1, 2, 4, 5, 42, 10, 11, 15, 18, 37, 23, 25, 22, 32, 59, 47, 53, 48, 83, 49, 110, 62, 51, 82, 63, 170, ..., %C A118480 The first negative term is at n=1473. - _T. D. Noe_, Apr 09 2009 %H A118480 T. D. Noe, <a href="/A118480/b118480.txt">Table of n, a(n) for n=1..2000</a> %F A118480 a(n) = (A002144(n) - A002145(n) - 2)/4. %t A118480 (Select[1 + 4Range@245, PrimeQ@# &] - Select[ -1 + 4Range@225, PrimeQ@# &] - 2)/4 %Y A118480 Cf. A022757, A007350, A007351, A038691. %K A118480 sign %O A118480 1,4 %A A118480 _Clark Kimberling_ and _Robert G. Wilson v_, May 04 2006