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
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Dec 03 2009
STATUS
approved