OFFSET
0,1
COMMENTS
See A107126 = {10, 14, 40, 59, 160, 412, ...} for the indices of primes.
LINKS
Patrick De Geest, Palindromic Wing Primes: (1)6(1), updated: June 25, 2017.
Brady Haran and Simon Pampena, Glitch Primes and Cyclops Numbers, Numberphile video (2015).
Makoto Kamada, Factorization of 11...11611...11, updated Dec 11 2018.
Index entries for linear recurrences with constant coefficients, signature (111,-1110,1000).
FORMULA
G.f.: (6 - 505*x + 400*x^2)/((1 - x)(1 - 10*x)(1 - 100*x)).
a(n) = 111*a(n-1) - 1110*a(n-2) + 1000*a(n-3) for n > 2.
E.g.f.: exp(x)*(10*exp(99*x) + 45*exp(9*x) - 1)/9. - Stefano Spezia, Jul 13 2024
MAPLE
A332116 := n -> (10^(2*n+1)-1)/9+5*10^n;
MATHEMATICA
Array[(10^(2 # + 1)-1)/9 + 5*10^# &, 15, 0]
PROG
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
M. F. Hasler, Feb 09 2020
STATUS
approved