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 A102146 a(n) = sigma(10^n - 1), where sigma(n) is the sum of positive divisors of n. 1
 13, 156, 1520, 15912, 148512, 2042880, 14508000, 162493344, 1534205464, 16203253248, 144451398000, 2063316971520, 14903272088640, 158269280832000, 1614847741624320, 17205180696931968, 144444514193267496 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Ray Chandler, Table of n, a(n) for n = 1..322 C. Caldwell, Sigma function. FORMULA a(n) = A000203(A002283(n)). - Ray Chandler, Apr 22 2017 MATHEMATICA DivisorSigma[1, 10^Range[20]-1] (* Harvey P. Dale, Jan 05 2012 *) PROG (PARI) a(n) = sigma(10^n-1); \\ Michel Marcus, Apr 22 2017 CROSSREFS Cf. A000203, A002283, A070528. Sequence in context: A077416 A192092 A297454 * A162768 A097827 A163084 Adjacent sequences:  A102143 A102144 A102145 * A102147 A102148 A102149 KEYWORD nonn AUTHOR Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Feb 14 2005 STATUS approved

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Last modified July 21 19:25 EDT 2019. Contains 325199 sequences. (Running on oeis4.)