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 A078096 #12 Jun 13 2020 09:50:16
%S A078096 1,1,3,19,1,7,1,105,37,163,73,43,45,649,3753,5323,423,3123,9981,12943
%N A078096 Least m such that P + m is a prime, where P is the n-th perfect number.
%C A078096 Some of the larger entries may only correspond to probable primes.
%e A078096 a(3)=3 because 496 + 3 is a prime.
%t A078096 e (* from A000043 *) = {2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, ...}; NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; Do[p = 2^(e[[n]] - 1)*(2^e[[n]] - 1); Print[NextPrim[p] - p], {n, 1, 20}]
%Y A078096 Cf. A000043, A000396, A061644, A078097.
%K A078096 nonn,hard,more
%O A078096 1,3
%A A078096 _Jason Earls_, Dec 01 2002
%E A078096 Edited and extended by _Robert G. Wilson v_, Dec 03 2002
%E A078096 a(19)-a(20) from _Jinyuan Wang_, Jun 13 2020