A180265 a(n) = smallest k such that sigma(k) = 14^n, or zero if no such k exists.

1, 13, 0, 1164, 15132, 230484, 2823492, 36705396, 508541124, 7194470556, 100696385244, 1503091145388, 19540184890044, 273550891167372, 3811871194625676, 53378900339114532, 727176010568075796, 10177815744800162004, 142523339476298463228, 1994910930816765350844, 27918212600229725023068

Offset

0,2

Links

Max Alekseyev, Table of n, a(n) for n = 0..100

Example

a(0)=1 since sigma(1)=14^0=1. a(1)=13 since sigma(13)=14. a(2)=0 since no N exists such that sigma(N)=14^2. a(6)=2823492=2^2*3*7*33613 since sigma(2823492)=14^6 is the first 6th power. a(7)=36705396=2^2*3*7*13*33613 since sigma(36705396)=14^7 is the first 7th power.

Crossrefs

Cf. A046528, A048251, A110077, A180460, A180461, A180462, A180463, A180464

Sequence in context: A094902 A252056 A096069 * A165400 A181154 A367303

Adjacent sequences: A180262 A180263 A180264 * A180266 A180267 A180268

Keyword

nonn

Author

Walter Kehowski, Aug 22 2010

Extensions

Edited (including b-file) by N. J. A. Sloane, Oct 05 2010

Terms a(25) onward from Max Alekseyev, Mar 04 2014

Status

approved