A139608 a(n) = 28*n + 8.

8, 36, 64, 92, 120, 148, 176, 204, 232, 260, 288, 316, 344, 372, 400, 428, 456, 484, 512, 540, 568, 596, 624, 652, 680, 708, 736, 764, 792, 820, 848, 876, 904, 932, 960, 988, 1016, 1044, 1072, 1100, 1128, 1156, 1184, 1212, 1240, 1268, 1296, 1324, 1352, 1380

Offset

0,1

Comments

Numbers of the 8th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.

References

A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 189. - From N. J. A. Sloane, Dec 01 2012

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Index to sequences related to polygonal numbers

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

Formula

a(n) = A057145(n+2,8).

a(n) = 2*a(n-1) - a(n-2); a(0)=8, a(1)=36. - Harvey P. Dale, Dec 14 2012

G.f.: 4*(2+5*x)/(x-1)^2. - R. J. Mathar, Jul 28 2016

From Elmo R. Oliveira, Apr 16 2024: (Start)

E.g.f.: 4*exp(x)*(2 + 7*x).

a(n) = 4*A017005(n) = A135628(n) + 8 = A316466(n+1) - A316466(n). (End)

Mathematica

Range[8, 7000, 28] (* Vladimir Joseph Stephan Orlovsky, Jul 13 2011 *)
LinearRecurrence[{2, -1}, {8, 36}, 50] (* or *) NestList[28+#&, 8, 50] (* Harvey P. Dale, Dec 14 2012 *)

Prog

(Magma) [4*(7*n + 2): n in [0..50]]; // Vincenzo Librandi, Jul 13 2011
(PARI) a(n)=28*n+8 \\ Charles R Greathouse IV, Oct 05 2011

Crossrefs

Cf. A017005, A057145, A135628, A139600, A316466.

Sequence in context: A184294 A057345 A048740 * A321778 A009923 A187287

Adjacent sequences: A139605 A139606 A139607 * A139609 A139610 A139611

Keyword

easy,nonn

Author

Omar E. Pol, Apr 27 2008

Status

approved