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A180265
a(n) = smallest k such that sigma(k) = 14^n, or zero if no such k exists.
6
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
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.
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