|
Search: id:A081271
|
|
| |
|
| 1, 13, 34, 64, 103, 151, 208, 274, 349, 433, 526, 628, 739, 859, 988, 1126, 1273, 1429, 1594, 1768, 1951, 2143, 2344, 2554, 2773, 3001, 3238, 3484, 3739, 4003, 4276, 4558, 4849, 5149, 5458, 5776, 6103, 6439, 6784, 7138, 7501, 7873, 8254, 8644, 9043, 9451
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Lies to the right of the y-axis of the triangle.
|
|
FORMULA
|
a(n)=C(n, 0)+12C(n, 1)+9C(n, 2); binomial transform of (1, 12, 9, 0, 0, 0, .....). a(n)=(9n^2+15n+2)/2. G.f.(1+10x-2x^2)/(1-x)^3.
a(0) = 1, a(n) = a(n-1) + 9*n + 3 for n > 0 - Gerald McGarvey (Gerald.McGarvey(AT)comcast.net), Aug 18 2004
a(n)=9*n+a(n-1)-6 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 09 2009]
|
|
EXAMPLE
|
For n=2, a(2)=9*2+1-6=13; n=3, a(3)=9*3+13-6=34; n=4, a(4)=9*4+34-6=64 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 09 2009]
|
|
CROSSREFS
|
Cf. A062741.
Sequence in context: A164539 A134864 A093100 this_sequence A081752 A069484 A089113
Adjacent sequences: A081268 A081269 A081270 this_sequence A081272 A081273 A081274
|
|
KEYWORD
|
easy,nonn,new
|
|
AUTHOR
|
Paul Barry (pbarry(AT)wit.ie), Mar 15 2003
|
|
|
Search completed in 0.002 seconds
|
