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 A128194 #15 Jul 17 2025 09:43:02 %S A128194 4432,3490,266,11069,1911,13619,27010,3982,140425,72738,21768,752305, %T A128194 4100791,4622387 %N A128194 Absolute value of second differences of A005849. %C A128194 In this sequence a(4) and a(6) are primes. Also a(2)+1, a(7)+1 and a(8)+1 are primes. And a(11)-1 is prime. These may at some future time begin three new sequences. %F A128194 a(n) = abs(A128193(n+1) - A128193(n)). - _Amiram Eldar_, Jul 17 2025 %e A128194 a(1) = 4432 because the first two values of first differences in A128193 are 140 and 4572. 4572-140 = 4432, the first second difference. %Y A128194 Cf. A005849 A128193. %K A128194 nonn,more %O A128194 1,1 %A A128194 _Enoch Haga_, Feb 18 2007 %E A128194 Offset changed to 1, a(9)-a(10) corrected and a(13)-a(14) added by _Amiram Eldar_, Jul 17 2025