A147601 First differences of A132355.

7, 4, 21, 8, 35, 12, 49, 16, 63, 20, 77, 24, 91, 28, 105, 32, 119, 36, 133, 40, 147, 44, 161, 48, 175, 52, 189, 56, 203, 60, 217, 64, 231, 68, 245, 72, 259, 76, 273, 80, 287, 84, 301, 88, 315, 92, 329, 96, 343, 100, 357

Offset

0,1

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).

Formula

G.f.: ( 7+4*x+7*x^2 ) / ((1-x)*(1+x))^2. - R. J. Mathar, Jun 21 2011

a(2*n) = A147587(n).

a(2*n+1) = 4*(n+1).

a(n) = (9 + 5*(-1)^n)*(1+n)/2. - Colin Barker, Jun 06 2012

E.g.f.: (1/2)*(5*(1-x)*exp(-x) + 9*(1+x)*exp(x)). - G. C. Greubel, Oct 25 2022

Mathematica

Differences[Sort[Table[9n^2+2n, {n, -30, 30}]]] (* or *) LinearRecurrence[ {0, 2, 0, -1}, {7, 4, 21, 8}, 60] (* Harvey P. Dale, Jun 04 2017 *)

Prog

(Magma) [(9 + 5*(-1)^n)*(1+n)/2: n in [0..60]]; // G. C. Greubel, Oct 25 2022
(SageMath) [(9 + 5*(-1)^n)*(1+n)/2 for n in range(61)] # G. C. Greubel, Oct 25 2022

Crossrefs

Cf. A132355, A147587.

Sequence in context: A279942 A279998 A063632 * A075536 A280336 A085047

Adjacent sequences: A147598 A147599 A147600 * A147602 A147603 A147604

Keyword

nonn,easy

Author

Paul Curtz, Nov 08 2008

Status

approved