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 A079887 #23 Dec 13 2022 12:07:07
%S A079887 1,1,3,3,5,1,5,1,5,3,5,9,7,1,7,3,5,11,1,5,13,13,5,11,15,3,5,11,15,1,3,
%T A079887 7,13,9,11,7,13,19,17,1,5,13,17,9,17,9,11,5,7,23,15,19,1,3,21,9,19,11,
%U A079887 25,21,7,25,17,1,13,5,15,23,11,17,5,25,23,9,3,5,19,15,27,25,13,1,19,29,27
%N A079887 Values of y-x where p runs through the primes of form 4k+1 and p=x^2+y^2, 0<=x<=y.
%C A079887 Also values of x where p runs through the primes of form 4k+1 and 2*p=x^2+y^2, 0<=x<y. - _Colin Barker_, Jul 07 2014
%F A079887 a(n) = A002330(n+1)-A002331(n+1). - _R. J. Mathar_, Jan 09 2017
%t A079887 pp = Select[ Range[200] // Prime, Mod[#, 4] == 1 &]; f[p_] := y - x /. ToRules[ Reduce[0 <= x <= y && p == x^2 + y^2, {x, y}, Integers]]; A079887 = f /@ pp (* _Jean-François Alcover_, Jan 15 2015 *)
%Y A079887 Cf. A002330, A002331, A002313, A002144, A079886.
%K A079887 nonn
%O A079887 1,3
%A A079887 _Benoit Cloitre_, Jan 13 2003