login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A025269 a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 5. 0
2, 1, 1, 1, 6, 27, 122, 555, 2530, 11564, 52994, 243467, 1121292, 5176432, 23952042, 111076279, 516217844, 2404051080, 11218106730, 52447788512, 245659502752, 1152673780946, 5417690242696, 25505048506311, 120257626246616, 567864679387562 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Conjecture: n*a(n) +4*(-2*n+3)*a(n-1) +12*(n-3)*a(n-2) +6*(2*n-9)*a(n-3) +16*(n-6)*a(n-4)=0. - R. J. Mathar, Nov 21 2014
G.f.: 1/2 - sqrt(16*x^4+12*x^3+12*x^2-8*x+1)/2. - Vaclav Kotesovec, Jan 25 2015
MATHEMATICA
nmax = 30; aa = ConstantArray[0, nmax]; aa[[1]] = 2; aa[[2]] = 1; aa[[3]] = 1; aa[[4]] = 1; Do[aa[[n]] = Sum[aa[[k]]*aa[[n-k]], {k, 1, n-1}], {n, 5, nmax}]; aa (* Vaclav Kotesovec, Jan 25 2015 *)
CROSSREFS
Sequence in context: A347781 A088152 A049270 * A265656 A137296 A329291
KEYWORD
nonn
AUTHOR
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 15:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)