A145523 Least integer k > 0 such that A000041(k) is divisible by 2^n.

1, 2, 11, 11, 15, 66, 66, 96, 96, 96, 96, 96, 3693, 15005, 18978, 18978, 18978, 43002, 55943, 972190, 1151214, 2799146, 15519397, 15519397, 15519397, 122101417, 210553237, 289585489, 473093534

Offset: 0

Author

M. F. Hasler, Oct 12 2008

Keywords

• more
• nonn

Comments

The requirement a(n) > 0 is somewhat arbitrary, chosen for agreement with A046641; a(n) >= 0 would have been possible, too, yielding a(0)=0.

a(29) > 10^9.

Crossrefs

Cf. A000041, A046641, A000123, A046063.

Programs

sh

i=1; c=1; while [ $c -le 21 ]; do echo -n `./A046641 $i`", "; c=`expr $c + 1`; i=`expr $i + $i`; done # M. F. Hasler, Oct 18 2008

Formula

a(n) = A046641(2^n).

Extensions

More terms from M. F. Hasler, Oct 18 2008

a(22)-a(28) from Max Alekseyev, Dec 16 2011