|
Search: id:A103832
|
|
|
| A103832 |
|
For even n, a(n)=2n+1, for odd n, a(n)=n(+1) |
|
+0
2
|
|
| 1, 2, 5, 12, 9, 30, 13, 56, 17, 90, 21, 132, 25, 182, 29, 240, 33, 306, 37, 380, 41, 462, 45, 552, 49, 650, 53, 756, 57, 870, 61, 992, 65, 1122, 69, 1260, 73, 1406, 77, 1560, 81, 1722, 85, 1892, 89, 2070, 93, 2256, 97, 2450, 101, 2652, 105, 2862, 109, 3080, 113
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
First the sum then the product of two successive integers.
|
|
FORMULA
|
G.f.: (1+3x^2)(1+2x-x^2)/((1-x)^3*(1+x)^3). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 30 2008]
|
|
EXAMPLE
|
a(4)=4+5=9, a(5)=5*6=30.
|
|
MATHEMATICA
|
Flatten[Table[{i + i + 1, (i + 1)(i + 2)}, {i, 0, 98, 2}]]
|
|
CROSSREFS
|
Cf. A103831.
Adjacent sequences: A103829 A103830 A103831 this_sequence A103833 A103834 A103835
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
Zak Seidov (zakseidov(AT)yahoo.com), Feb 17 2005, Feb 18 2005
|
|
EXTENSIONS
|
Edited by njas, Aug 29 2008 at the suggestion of R. J. Mathar
|
|
|
Search completed in 0.002 seconds
|
