A126806 Smallest number k such that 2^n divides A066796(k) = Sum(i=1,k,binomial(2*i,i)).

1, 2, 2, 11, 11, 46, 46, 707, 707, 707, 2831, 2831, 11955, 11962, 45256, 45256, 191400, 533697, 533697, 533697

Offset: 1

Author

Alexander Adamchuk, Feb 23 2007

Keywords

• more
• nonn

Comments

a(17)>75000. - Robert G. Wilson v, Feb 25 2007

Crossrefs

Cf. A066796.

Programs

Mathematica

sb[1] = 2; sb[k_] := sb[k] = sb[k - 1] + Binomial[2k, k]; f[n_] := Block[{k = 1}, While[ Mod[sb@k, 2^n] != 0, k++ ]; k]; Do[Print@ f@n, {n, 0, 15}] (* Robert G. Wilson v, Feb 25 2007 *)

Extensions

a(11)-a(16) from Robert G. Wilson v, Feb 25 2007

a(17) from Vaclav Kotesovec, Jun 07 2019

a(18)-a(20) from Vaclav Kotesovec, Jun 12 2019