OFFSET
0,1
COMMENTS
See A183181 = {4, 5, 8, 11, 1244, 1685, ...} for the indices of primes.
LINKS
Index entries for linear recurrences with constant coefficients, signature (111,-1110,1000).
FORMULA
a(n) = 7*A138148(n) + 6*10^n.
G.f.: (6 + 101*x - 800*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.
MAPLE
A332176 := n -> 7*(10^(n*2+1)-1)/9 - 10^n;
MATHEMATICA
Array[7 (10^(2 # + 1) - 1)/9 - 10^# &, 15, 0]
PROG
CROSSREFS
Cf. A138148 (cyclops numbers with binary digits only).
KEYWORD
nonn,base,easy
AUTHOR
M. F. Hasler, Feb 08 2020
STATUS
approved