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 A077650 Initial decimal digit of sigma(n), the sum of divisors of n. 3
 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, 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, 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A000030(A000203(n)). MATHEMATICA Table[First[IntegerDigits[DivisorSigma[1, w]]], {w, 1, 128}] PROG (PARI) a(n) = digits(sigma(n))[1]; \\ Michel Marcus, Nov 18 2017 CROSSREFS Cf. A000030, A000203, A067342. Sequence in context: A010613 A299693 A134688 * A244669 A316570 A105853 Adjacent sequences:  A077647 A077648 A077649 * A077651 A077652 A077653 KEYWORD base,nonn AUTHOR Labos Elemer, Nov 19 2002 STATUS approved

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Last modified September 16 18:45 EDT 2019. Contains 327117 sequences. (Running on oeis4.)