A139618 - OEIS

A139618

a(n) = 153*n + 18.

18, 171, 324, 477, 630, 783, 936, 1089, 1242, 1395, 1548, 1701, 1854, 2007, 2160, 2313, 2466, 2619, 2772, 2925, 3078, 3231, 3384, 3537, 3690, 3843, 3996, 4149, 4302, 4455, 4608, 4761, 4914, 5067, 5220, 5373, 5526, 5679, 5832, 5985

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OFFSET

0,1

COMMENTS

Numbers of the 18th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. Also, numbers of the 18th column in the square array A057145.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..5000

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

From Elmo R. Oliveira, Apr 04 2024: (Start)

G.f.: 9*(2+15*x)/(x-1)^2.

E.g.f.: 9*exp(x)*(2 + 17*x).

a(n) = 9*(A008599(n) + 2).

a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

MATHEMATICA

153*Range[0, 40]+18 (* or *) LinearRecurrence[{2, -1}, {18, 171}, 40] (* Harvey P. Dale, May 25 2016 *)

PROG