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Search: id:A102836
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| A102836 |
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Numbers whose powers in their canonical factorization lie in the geometric progression 1,2,4,.. |
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+0
1
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| 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
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The first term not in A095990 is 11250.
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EXAMPLE
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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.
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PROGRAM
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(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", ")) ) }
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CROSSREFS
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Cf. A095990.
Sequence in context: A089219 A102835 A095990 this_sequence A143928 A074173 A092068
Adjacent sequences: A102833 A102834 A102835 this_sequence A102837 A102838 A102839
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Feb 27 2005
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