Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A025262
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A025262 a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 4. +0
3
1, 1, 1, 3, 8, 23, 68, 207, 644, 2040, 6558, 21343, 70186, 232864, 778550, 2620459, 8872074, 30195288, 103246502, 354508628, 1221846856, 4225644866, 14659644348, 51002664023, 177909901566, 622093882290, 2180123564130, 7656055966092 (list; graph; listen)
OFFSET

1,4

LINKS

M. Somos, Number Walls in Combinatorics.

FORMULA

G.f.: (1-sqrt(1-4x+4x^3))/2. Satisfies A(x)-A(x)^2=x-x^3 - Michael Somos, Aug 04, 2000.

PROGRAM

(PARI) a(n)=polcoeff((1-sqrt(1-4*x+4*x^3+x*O(x^n)))/2, n)

CROSSREFS

Essentially same as A056010.

Sequence in context: A025578 A038151 A057198 this_sequence A056010 A002712 A005960

Adjacent sequences: A025259 A025260 A025261 this_sequence A025263 A025264 A025265

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu)

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified July 19 08:04 EDT 2008. Contains 142098 sequences.


AT&T Labs Research