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 A077086 #18 Jan 24 2025 18:32:17 %S A077086 0,1,3,6,0,8,7,13,5,12,4,14,10,0,7,18,3,20,2,32,4,24,12,31,11,40,16, %T A077086 30,12,32,31,48,6,48,43,38,22,56,34,42,12,44,40,78,72,48,28,57,36,72, %U A077086 26,54,12,72,48,80,10,60,48,62,34,8,23,84,60,68,58,96,48,72,51,74,40,10 %N A077086 Remainder when sigma(n+1) is divided by sigma(n). %H A077086 Seiichi Manyama, <a href="/A077086/b077086.txt">Table of n, a(n) for n = 1..10000</a> %F A077086 a(n) = Mod(A000203(n+1), A000203(n)). %e A077086 a(7) = 7 since sigma(7) = 8, sigma(8) = 15, and 15 = 1*8 + 7. %t A077086 a[n_]:=Mod[DivisorSigma[1,n+1],DivisorSigma[1,n]]; Array[a,74] (* _Stefano Spezia_, Jan 24 2025 *) %o A077086 (PARI) a(n) = sigma(n+1) % sigma(n); \\ _Michel Marcus_, Dec 26 2013 %Y A077086 Cf. A000203, A000668 (fixed points), A002961, A067081. %K A077086 nonn %O A077086 1,3 %A A077086 _Labos Elemer_, Oct 31 2002