|
Search: id:A140673
|
|
| |
|
| 0, 9, 21, 36, 54, 75, 99, 126, 156, 189, 225, 264, 306, 351, 399, 450, 504, 561, 621, 684, 750, 819, 891, 966, 1044, 1125, 1209, 1296, 1386, 1479, 1575, 1674, 1776, 1881, 1989, 2100, 2214, 2331, 2451, 2574, 2700, 2829, 2961, 3096
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
FORMULA
|
a(n) = A055998(n)*3 = (3*n^2 + 15*n)/2 = n(3n+15)/2.
a(n)=3*n+a(n-1)+3 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
|
|
EXAMPLE
|
For n=2, a(2)=3*2+0+3=9; n=3, a(3)=3*3+9+3=21; n=4, a(4)=3*4+21+3=36 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
|
|
MATHEMATICA
|
lst={}; Do[AppendTo[lst, 3*n*(n+5)/2], {n, 0, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 06 2008]
Table[Sum[i + n - 3, {i, 6, n}], {n, 5, 52}] [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 11 2009]
|
|
CROSSREFS
|
Cf. A000326, A005449, A045943, A115067, A140090, A140091, A059845, A140672, A140674, A140675, A055998.
The generalized pentagonal numbers b*n+3*n*(n-1)/2, for b = 1 through 12, form sequences A000326, A005449, A045943, A115067, A140090, A140091, A059845, A140672, A140673, A140674, A140675, A151542.
Sequence in context: A043112 A043892 A146069 this_sequence A059993 A036704 A107890
Adjacent sequences: A140670 A140671 A140672 this_sequence A140674 A140675 A140676
|
|
KEYWORD
|
easy,nonn,new
|
|
AUTHOR
|
Omar E. Pol (info(AT)polprimos.com), May 22 2008
|
|
|
Search completed in 0.002 seconds
|
