This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A132459 Sums of squared coefficients in the negative powers of the Catalan function: a(n) = Sum_{k=1..n+1} [x^(n-k+1)] 1/C(x^2)^k, where C(x) is the g.f. of A000108. 1
 1, 1, 2, 5, 11, 18, 30, 45, 101, 171, 483, 702, 2745, 3406, 21215, 23237, 202627, 205701, 2169260, 2138431, 24770064, 24197219, 294389605, 286927242, 3600713132, 3508785697, 45050653316, 43916201874, 574363373312 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS PROG (PARI) {a(n)=local(Catalan=2/(1+sqrt(1-4*x^2 +x*O(x^n)))); sum(k=1, n+1, polcoeff(Catalan^-k, n-k+1)^2)} CROSSREFS Cf. A132461; A000108 (Catalan). Sequence in context: A298375 A260037 A132455 * A308517 A101057 A045362 Adjacent sequences:  A132456 A132457 A132458 * A132460 A132461 A132462 KEYWORD nonn AUTHOR Paul D. Hanna, Aug 21 2007 STATUS approved

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

Last modified October 20 20:23 EDT 2019. Contains 328273 sequences. (Running on oeis4.)