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

Author

Paul Curtz, Dec 03 2009

Keywords

• nonn
• easy

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).

Programs

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

Mathematica

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

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