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Search: id:A095990
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| A095990 |
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Numbers with prime signature (1,2). |
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+0
5
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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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Numbers of the form p*q^2 where p and q are primes with p < q.
A054753 contains natural numbers with prime signatures (2,1) and (1,2). a(n) is a subsequence of A071365.
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EXAMPLE
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18 = 2*3*3, 50 = 2*5*5, 75 = 3*5*5, 98 = 2*7*7, 147 = 3*7*7, ...
18 is the first term in A055932 but not in A025487 (least prime signatures)
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MATHEMATICA
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Take[ Sort[ Flatten[ Table[ Prime[p]*Prime[q]^2, {q, 2, 16}, {p, q - 1}]]], 46] (from Robert G. Wilson v Jul 23 2004)
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CROSSREFS
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Cf. A054753, A071365, A095904, A096156.
Sequence in context: A093617 A089219 A102835 this_sequence A102836 A074173 A092068
Adjacent sequences: A095987 A095988 A095989 this_sequence A095991 A095992 A095993
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KEYWORD
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easy,nonn
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AUTHOR
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Alford Arnold (Alford1940(AT)aol.com), Jul 18 2004
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 23 2004
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