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A210672 a(0)=1; thereafter a(n) = 2*Sum_{k=1..n} binomial(2n,2k)*a(n-k). 6
1, 2, 26, 842, 50906, 4946282, 704888186, 138502957322, 35887046307866, 11855682722913962, 4863821092813045946, 2425978759725443056202, 1445750991051368583278426, 1014551931766896667943384042, 828063237870027116855857421306, 777768202388460616924079724057482 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Consider the sequence defined by a(0)=1; thereafter a(n) = 2*Sum_{k=1..n} binomial(2n,2k)*a(n-k). For k = -3, -2, -1, 1, 2, 3 this is A210676, A210657, A028296, A094088, A210672, A210674.

LINKS

Table of n, a(n) for n=0..15.

MAPLE

f:=proc(n, k) option remember;  local i;

if n=0 then 1

else k*add(binomial(2*n, 2*i)*f(n-i, k), i=1..floor(n)); fi; end;

g:=k->[seq(f(n, k), n=0..40)];

g(2);

CROSSREFS

Sequence in context: A156212 A138524 A059516 * A173103 A002704 A015215

Adjacent sequences:  A210669 A210670 A210671 * A210673 A210674 A210675

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 28 2012

STATUS

approved

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Last modified July 23 16:33 EDT 2014. Contains 244870 sequences.