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A098475 a(n) is the smallest integer k for which sigma_n(k) <= sigma_n(k-1) where sigma_n(k) = sum of the n-th powers of the divisors of k. 1
3, 5, 7, 25, 61, 145, 361, 853, 1969, 4489, 10069, 22273, 48781, 105949, 228589, 490405, 1046977, 2225965, 4715401, 9956977, 20965213, 44031361, 92262349, 192920785, 402629257, 838827577, 1744784389, 3623814865, 7516104565 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

a(n) has to be larger than the solution to Zeta(n)*(x-1)^n=x^n.

LINKS

Table of n, a(n) for n=0..28.

EXAMPLE

a(1)=5 since sigma(1)=1,sigma(2)=3,sigma(3)=4, sigma(4)=7, but sigma(5)=6.

PROG

(PARI) a(n) = {my(k = 2); while(sigma(k, n) > sigma(k-1, n), k++); k; } \\ Michel Marcus, Aug 18 2013

CROSSREFS

Sequence in context: A108313 A045966 A146148 * A131039 A294924 A249544

Adjacent sequences:  A098472 A098473 A098474 * A098476 A098477 A098478

KEYWORD

nonn

AUTHOR

John L. Drost, Oct 26 2004

STATUS

approved

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Last modified March 3 10:38 EST 2021. Contains 341762 sequences. (Running on oeis4.)