|
| |
|
|
A099185
|
|
Iterated octahedral numbers, starting at a(0) = 2.
|
|
1
|
|
|
|
2, 6, 146, 2074806, 5954444157018557346, 140744820294208035204656447906095566299588102457814757606, 1858685896365056640452604182778243755878210128325493631436394942328487801924642707284183892998994140529418479176238949509991689659112331788418314832322689820822344586546
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,1
|
|
|
REFERENCES
|
Conway, J. H. and Guy, R. K. The Book of Numbers. New York: Springer-Verlag, p. 50, 1996.
Dickson, L. E. History of the Theory of Numbers, Vol. 2: Diophantine Analysis. New York: Chelsea, 1952.
J. V. Post, "Iterated Triangular numbers", preprint.
|
|
|
LINKS
|
Vincenzo Librandi, Table of n, a(n) for n = 0..7
Eric Weisstein's World of Mathematics, "Octahedral Number."
|
|
|
FORMULA
|
a(0) = 2, a(n+1) = oct(a(n)) = (2*a(n)^3 + a(n))/3.
|
|
|
MATHEMATICA
|
RecurrenceTable[{a[0]==2, a[n+1]==(2 a[n]^3 + a[n])/3}, a, {n, 6}] (* Vincenzo Librandi, Sep 16 2018 *)
|
|
|
CROSSREFS
|
Cf. A007501, A005900.
Sequence in context: A333444 A274986 A024397 * A015173 A122570 A088430
Adjacent sequences: A099182 A099183 A099184 * A099186 A099187 A099188
|
|
|
KEYWORD
|
easy,nonn,less
|
|
|
AUTHOR
|
Jonathan Vos Post, Nov 15 2004
|
|
|
EXTENSIONS
|
Edited by Jianing Song, Sep 16 2018
|
|
|
STATUS
|
approved
|
| |
|
|
