OFFSET
0,1
COMMENTS
The corresponding right Aurifeuillian factor is A220986.
LINKS
Wikipedia, Cunningham Project
FORMULA
a(n) = 10^(8n+4) - 10^(7n+4) + 5 * 10^(6n+3) - 2 * 10^(5n+3) + 7 * 10^(4n+2) - 2 * 10^(3n+2) + 5 * 10^(2n+1) - 10^(n+1) + 1.
Aurifeuillian factorization: 10^(20n+10) + 1 = (10^(4n+2) + 1) * a(n) * A220986(n).
MATHEMATICA
Table[10^(8n+4) - 10^(7n+4) + 5 * 10^(6n+3) - 2 * 10^(5n+3) + 7 * 10^(4n+2) - 2 * 10^(3n+2) + 5 * 10^(2n+1) - 10^(n+1) + 1, {n, 0, 20}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Stuart Clary, Dec 27 2012
STATUS
approved