A169607 a(n) = 7*A000330(n).

0, 7, 35, 98, 210, 385, 637, 980, 1428, 1995, 2695, 3542, 4550, 5733, 7105, 8680, 10472, 12495, 14763, 17290, 20090, 23177, 26565, 30268, 34300, 38675, 43407, 48510, 53998, 59885, 66185, 72912, 80080, 87703, 95795, 104370, 113442, 123025, 133133, 143780, 154980, 166747, 179095

Offset

0,2

Comments

From R. J. Mathar, Jun 30 2013: (Start)

The array view of A001477 is

0, 2, 5, 9, 14, 20,

1, 4, 8, 13, 19, 26,

3, 7, 12, 18, 25, 33,

6, 11, 17, 24, 32, 41,

10, 16, 23, 31, 40, 50,

15, 22, 30, 39, 49, 60,

and a(n) is the hook Sum_{k=0..n} A(n,k) + Sum_{r=0..n-1} A(r,n). (End)

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Formula

G.f.: 7*x*(1+x)/(x-1)^4.

a(n) = Sum_{k=0..n} A169603(n,k).

a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4). - Vincenzo Librandi, Jul 02 2012

Mathematica

CoefficientList[Series[7*x*(1+x)/(x-1)^4, {x, 0, 50}], x] (* Vincenzo Librandi, Jul 02 2012 *)

Prog

(Magma)  I:=[0, 7, 35, 98]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..50]]; // Vincenzo Librandi, Jul 02 2012

Crossrefs

Sequence in context: A077536 A256391 A152744 * A130884 A037092 A210368

Adjacent sequences: A169604 A169605 A169606 * A169608 A169609 A169610

Keyword

nonn,easy

Author

Paul Curtz, Dec 03 2009

Status

approved