|
| |
| |
|
|
|
10, 24, 42, 64, 90, 120, 154, 192, 234, 280, 330, 384, 442, 504, 570, 640, 714, 792, 874, 960, 1050, 1144, 1242, 1344, 1450, 1560, 1674, 1792, 1914, 2040, 2170, 2304, 2442, 2584, 2730, 2880, 3034, 3192, 3354, 3520, 3690, 3864, 4042, 4224, 4410, 4600
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Numbers such that 8 (8 + n) is a perfect square.
|
|
|
LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (3,-3,1).
|
|
|
FORMULA
| a(n+1)= 2*n*n +12*n +10. [Frank Ellermann (hmdmhdfmhdjmzdtjmzdtzktdkztdjz(AT)gmail.com)]
a(n)=sum(sum(j-k, j=4..n),k=0..n):, n>=4 . - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 11 2007
|
|
|
MAPLE
| a:=n->sum(sum(j-k, j=4..n), k=0..n): seq(a(n), n=4..49); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 11 2007
|
|
|
MATHEMATICA
| Select[ Range[10000], IntegerQ[ Sqrt[ 8(8 + # )]] & ]
|
|
|
PROG
| (PARI) a(n)=2*n*(n+4) \\ Charles R Greathouse IV, Dec 07 2011
|
|
|
CROSSREFS
| Cf. 7: A067727, 6: A067726, 5: A067724, 3: A067725.
Sequence in context: A101156 A162817 A103573 * A058504 A126911 A135285
Adjacent sequences: A067725 A067726 A067727 * A067729 A067730 A067731
|
|
|
KEYWORD
| nonn,easy
|
|
|
AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 05 2002
|
| |
|
|
