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 A077650 #11 Nov 18 2017 09:06:59 %S A077650 1,3,4,7,6,1,8,1,1,1,1,2,1,2,2,3,1,3,2,4,3,3,2,6,3,4,4,5,3,7,3,6,4,5, %T A077650 4,9,3,6,5,9,4,9,4,8,7,7,4,1,5,9,7,9,5,1,7,1,8,9,6,1,6,9,1,1,8,1,6,1, %U A077650 9,1,7,1,7,1,1,1,9,1,8,1,1,1,8,2,1,1,1,1,9,2,1,1,1,1,1,2,9,1,1,2,1,2,1,2,1 %N A077650 Initial decimal digit of sigma(n), the sum of divisors of n. %H A077650 Antti Karttunen, <a href="/A077650/b077650.txt">Table of n, a(n) for n = 1..10000</a> %H A077650 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A077650 a(n) = A000030(A000203(n)). %t A077650 Table[First[IntegerDigits[DivisorSigma[1, w]]], {w, 1, 128}] %o A077650 (PARI) a(n) = digits(sigma(n))[1]; \\ _Michel Marcus_, Nov 18 2017 %Y A077650 Cf. A000030, A000203, A067342. %K A077650 base,nonn %O A077650 1,2 %A A077650 _Labos Elemer_, Nov 19 2002