A102836 Numbers whose powers in their canonical factorization lie in the geometric progression 1,2,4,..

18, 50, 75, 98, 147, 242, 245, 338, 363, 507, 578, 605, 722, 845, 847, 867, 1058, 1083, 1183, 1445, 1587, 1682, 1805, 1859, 1922, 2023, 2523, 2527, 2645, 2738, 2883, 3179, 3362, 3698, 3703, 3757, 3971, 4107, 4205, 4418, 4693, 4805, 5043, 5547, 5618, 5819

Offset

1,1

Comments

The first term not in A095990 is 11250.

Links

Table of n, a(n) for n=1..46.

Example

Canonical factorization of 11250 = 2^1 * 3^2 * 5*4 or 2,3,5 raised to powers 1,2,4 which is a geometric progression. 11250 is not shown in the list above.

Prog

(PARI) \Numbers whose factors are primes to perfect powers in a geometric progression. geoprog(n, m) = { local(a, x, j, nf, fl=0); for(x=1, n, a=factor(x); nf=omega(x); for(j=1, nf, if(a[j, 2]==2^(j-1), fl=1, fl=0; break); ); if(fl&nf>1, print1(x", ")) ) }

Crossrefs

Cf. A095990.

Sequence in context: A089219 A102835 A095990 * A217750 A180292 A143928

Adjacent sequences: A102833 A102834 A102835 * A102837 A102838 A102839

Keyword

easy,nonn

Author

Cino Hilliard, Feb 27 2005

Status

approved