|
| |
| |
|
|
|
0, 2, 10, 20, 36, 54, 78, 104, 136, 170, 210, 252, 300, 350, 406, 464, 528, 594, 666, 740, 820, 902, 990, 1080, 1176, 1274, 1378, 1484, 1596, 1710, 1830, 1952, 2080, 2210, 2346, 2484, 2628, 2774, 2926, 3080, 3240, 3402, 3570, 3740
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Sequence found by reading the line from 0, in the direction 0, 2,... and the same line from 0, in the direction 0, 10,..., in the square spiral whose vertices are the triangular numbers A000217.
a(n) = 2*A006578(n) - A002378(n)/2 = 2*A035608(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 07 2010]
|
|
|
LINKS
| O. E. Pol, Determinacion geometrica de los numeros primos y perfectos.
|
|
|
FORMULA
| Array read by rows: row n gives 8*n^2 + 2n, 8*(n+1)^2 - 6(n+1).
a(n) = 2*floor((n + 1/4)^2). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 07 2010]
|
|
|
EXAMPLE
| Array begins:
0, 2
10, 20
36, 54
78, 104
|
|
|
CROSSREFS
| Cf. A000217, A033585, A046092, A139271, A077221, A139591, A139593, A139595, A139596, A139597, A139598.
Sequence in context: A038103 A177150 A165551 * A120552 A090220 A164882
Adjacent sequences: A139589 A139590 A139591 * A139593 A139594 A139595
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Omar E. Pol (info(AT)polprimos.com), May 03 2008
|
| |
|
|
