OFFSET
0,1
COMMENTS
Indices of prime terms: {0, 1, 3, 7, 10, 12, 480, 949, ...} = A183178.
LINKS
Index entries for linear recurrences with constant coefficients, signature (111,-1110,1000).
FORMULA
a(n) = 7*A138148(n) + 2*10^n.
G.f.: (2 + 505*x - 1200*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
A332172 := n -> 7*(10^(n*2+1)-1)/9 -5*10^n;
MATHEMATICA
Array[7 (10^(2 # +1)-1)/9 -5*10^# &, 15, 0]
PROG
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
M. F. Hasler, Feb 06 2020
STATUS
approved