A178854 - OEIS

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A178854

Asymptotic value of odd Catalan numbers mod 2^n.

0, 1, 1, 5, 13, 29, 29, 93, 221, 221, 733, 1757, 3805, 7901, 7901, 24285, 57053, 122589, 122589, 384733, 384733, 384733, 2481885, 2481885, 10870493, 10870493, 10870493, 10870493, 145088221

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OFFSET

0,4

COMMENTS

For every n, the odd Catalan numbers C(2^m-1) are eventually constant mod 2^n (namely for m >= n-1): then a(n) is the asymptotic value of the remainder.

LINKS

Table of n, a(n) for n=0..28.

Shu-Chung Liu and Jean C.-C. Yeh, Catalan numbers modulo 2^k, J. Int. Seq. 13 (2010), article 10.5.4.

FORMULA

a(n) = remainder(Catalan(2^m-1), 2^n) for any m >= n-1.

EXAMPLE

The odd Catalan numbers mod 2^6=64 are 1,5,45,61,29,29,29, so a(6)=29.

MAPLE

A000108 := proc(n) binomial(2*n, n)/(n+1) ; end proc:

A038003 := proc(n) A000108(2^n-1) ; end proc:

A178854 := proc(n) if n = 0 then 0; else modp(A038003(n-1), 2^n) ; end if; end proc:

for n from 0 do printf("%d, \n", A178854(n)) ; end do: # R. J. Mathar, Jun 28 2010

MATHEMATICA

(* first do *) Needs["DiscreteMath`CombinatorialFunctions`"] (* then *) f[n_] := Mod[ CatalanNumber[2^n - 1], 2^n]; Array[f, 25, 0] (* Robert G. Wilson v, Jun 28 2010 *)

CROSSREFS

Cf. A038003 (odd Catalan numbers).

Sequence in context: A226618 A321770 A322926 * A224339 A368546 A133204

Adjacent sequences: A178851 A178852 A178853 * A178855 A178856 A178857

KEYWORD

nonn

AUTHOR

David A. Madore, Jun 18 2010

EXTENSIONS

a(12)-a(24) from Robert G. Wilson v, Jun 28 2010

a(25)-a(28) from Robert G. Wilson v, Jul 23 2010

STATUS

approved