OFFSET
1,1
LINKS
Daniel Suteu, Table of n, a(n) for n = 1..412
Wikipedia, Sierpinski Number
EXAMPLE
78557 * 2^1 + 1 = 157115 = 5 * 7 * 67^2. So a(1) = 67.
78557 * 2^2 + 1 = 314229 = 3 * 104743. So a(2) = 104743.
MATHEMATICA
Table[FactorInteger[2^n * 78557 + 1][[-1, 1]], {n, 30}] (* Alonso del Arte, Jan 01 2017 *)
PROG
(PARI) a(n) = my(k=78557*2^n+1); factor(k)[omega(k), 1] \\ Felix Fröhlich, Jan 01 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 19 2016
STATUS
approved