|
Search: id:A007202
|
|
|
| A007202 |
|
Crystal ball sequence for hexagonal close-packing.
(Formerly M4899)
|
|
+0
1
|
|
| 1, 13, 57, 153, 323, 587, 967, 1483, 2157, 3009, 4061, 5333, 6847, 8623, 10683, 13047, 15737, 18773, 22177, 25969, 30171, 34803, 39887, 45443, 51493, 58057, 65157, 72813, 81047, 89879, 99331, 109423, 120177, 131613, 143753, 156617
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
REFERENCES
|
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=0..1000
Index entries for crystal ball sequences
J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (Abstract, pdf, ps).
|
|
FORMULA
|
Nearest integer to (7/8)*( (n+1)^4 - n^4 ).
|
|
MAPLE
|
G.f.: (x^4+10*x^3+20*x^2+10*x+1)/(x-1)^4/(x+1).
|
|
PROGRAM
|
(PARI) j=[]; for(n=0, 75, j=concat(j, round((7/8)*((n+1)^4-n^4)))); j
|
|
CROSSREFS
|
Sequence in context: A005902 A051798 A061161 this_sequence A147384 A147011 A147019
Adjacent sequences: A007199 A007200 A007201 this_sequence A007203 A007204 A007205
|
|
KEYWORD
|
nonn,easy,nice
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com) and J. H. Conway (conway(AT)math.princeton.edu)
|
|
EXTENSIONS
|
More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jul 14 2001
|
|
|
Search completed in 0.002 seconds
|
