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A169607
a(n) = 7*A000330(n).
3
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)
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
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Dec 03 2009
STATUS
approved