A091693 - OEIS

A091693

a(n) = (n*10^n - n + 9)/9.

1, 2, 23, 334, 4445, 55556, 666667, 7777778, 88888889, 1000000000, 11111111111, 122222222222, 1333333333333, 14444444444444, 155555555555555, 1666666666666666, 17777777777777777, 188888888888888888

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..17.

Index entries for linear recurrences with constant coefficients, signature (22,-141,220,-100).

FORMULA

G.f.: ( 1-20*x+120*x^2-110*x^3 ) / ( (10*x-1)^2*(x-1)^2 ). - R. J. Mathar, Feb 14 2015

a(n) = 22*a(n-1) - 141*a(n-2) + 220*a(n-3) - 100*a(n-4). - Wesley Ivan Hurt, May 17 2023

CROSSREFS

Cf. A091686.

Sequence in context: A077203 A173935 A216549 * A276025 A211925 A277830

Adjacent sequences: A091690 A091691 A091692 * A091694 A091695 A091696

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Jan 29 2004

STATUS

approved