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A172175
a(n) = 110*a(n-1) + 1.
1
1, 111, 12211, 1343211, 147753211, 16252853211, 1787813853211, 196659523853211, 21632547623853211, 2379580238623853211, 261753826248623853211, 28792920887348623853211, 3167221297608348623853211, 348394342736918348623853211, 38323377701061018348623853211
OFFSET
1,2
COMMENTS
Sum of pairs of integers given in A162849. Sum of digits give A000225.
FORMULA
From Colin Barker, Oct 02 2015: (Start)
a(n) = 111*a(n-1) - 110*a(n-2) for n>2.
G.f.: 1 / ((1-x)*(1-110*x)). (End)
MATHEMATICA
a = {1}; Do[AppendTo[a, 110 a[[n-1]] + 1], {n, 2, 15}]; a (* Michael De Vlieger, Oct 02 2015 *)
PROG
(PARI) Vec(1/((x-1)*(110*x-1)) + O(x^30)) \\ Colin Barker, Oct 02 2015
(SageMath) [((110)^n -1)/109 for n in (1..50)] # G. C. Greubel, Apr 26 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Mark Dols, Jan 28 2010
STATUS
approved