A139613 a(n) = 78*n + 13.

13, 91, 169, 247, 325, 403, 481, 559, 637, 715, 793, 871, 949, 1027, 1105, 1183, 1261, 1339, 1417, 1495, 1573, 1651, 1729, 1807, 1885, 1963, 2041, 2119, 2197, 2275, 2353, 2431, 2509, 2587, 2665, 2743, 2821, 2899, 2977, 3055, 3133

Offset

0,1

Comments

Numbers of the 13th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. Also, numbers of the 13th 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 03 2024: (Start)

G.f.: 13*(1+5*x)/(x-1)^2.

E.g.f.: 13*exp(x)*(1 + 6*x).

a(n) = 13*A016921(n).

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

Mathematica

78*Range[0, 50] + 13 (* Paolo Xausa, Apr 04 2024 *)

Prog

(Magma) [13*(6*n + 1): n in [0..60]]; // Vincenzo Librandi, Jul 23 2011
(PARI) a(n)=78*n+13 \\ Charles R Greathouse IV, Oct 05 2011

Crossrefs

Cf. A016921, A057145, A139600.

Sequence in context: A347686 A131700 A156947 * A212956 A188352 A162631

Adjacent sequences: A139610 A139611 A139612 * A139614 A139615 A139616

Keyword

easy,nonn

Author

Omar E. Pol, Apr 27 2008

Status

approved