|
Search: id:A085601
|
|
|
| A085601 |
|
a(n) = 2 * (4^n + 2^n) + 1. |
|
+0
3
|
|
| 5, 13, 41, 145, 545, 2113, 8321, 33025, 131585, 525313, 2099201, 8392705, 33562625, 134234113, 536903681, 2147549185, 8590065665, 34360000513, 137439477761, 549756862465, 2199025352705, 8796097216513, 35184380477441
(list; graph; listen)
|
|
|
OFFSET
|
0,1
|
|
|
COMMENT
|
1. Begin with a square tile.
2. Place square tiles on each edge to form a diamond shape.
3. Count the tiles: a(0) = 5.
4. Add tiles to fill the enclosing square.
5. Go to step 2.
|
|
FORMULA
|
a(n)=7*a(n-1)-14*a(n-2)+8*a(n-3). G.f.: -(5-22*x+20*x^2)/((x-1)*(2*x-1)*(4*x-1)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 20 2009]
|
|
CROSSREFS
|
Cf. A028403, A046142, A056640, A064412.
Sequence in context: A046717 A080925 A164907 this_sequence A147718 A111009 A012172
Adjacent sequences: A085598 A085599 A085600 this_sequence A085602 A085603 A085604
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Jul 07 2003
|
|
EXTENSIONS
|
Edited by Franklin T. Adams-Watters (franktaw(AT)netscape.net) and Don Reble (djr(AT)nk.ca), Aug 15 2006
|
|
|
Search completed in 0.002 seconds
|
