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