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Search: id:A141572
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| A141572 |
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Products of pairs of the infinite list of primes generated by flattening the factorizations of the integers. |
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1
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| 2, 6, 10, 6, 14, 4, 9, 10, 22, 6, 26, 21, 10, 4, 34, 6, 57, 4, 15, 14, 253, 4, 6, 25, 26, 9, 6, 14, 58, 15, 62, 4, 4, 33, 34, 35, 4, 9, 74, 57, 26, 4, 205, 6, 301, 4, 33, 15, 46, 94, 4, 6, 49, 10, 15, 34, 26, 106, 9, 15, 22, 4, 21, 38, 1711, 4, 15, 122, 93, 21, 4, 4, 4, 65, 6, 737, 4
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Factorize n to its full extent into the list 1, 2, 3, 2*2, 5, 2*3, 7, 2*2*2, 3*3, 2*5, 11, 2*2*3,..
Remove delimiting commas and the multiplication signs and build new products by pairing construction, all but the first term are in A001358.
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MAPLE
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pflat := proc(nmax) local a, ifs, n, p, c ; a := [1] ; for n from 2 to nmax do ifs := ifactors(n)[2] ; for p in ifs do q := op(1, p) ; for c from 1 to op(2, p) do a := [op(a), q] ; od: od: od: a ; end: pL := pflat(120) : for n from 1 to nops(pL)-2 by 2 do printf("%d, ", op(n, pL)*op(n+1, pL)) ; od: # R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 21 2008
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CROSSREFS
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Cf. A000040.
Sequence in context: A004055 A077933 A144762 this_sequence A141257 A122882 A136700
Adjacent sequences: A141569 A141570 A141571 this_sequence A141573 A141574 A141575
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KEYWORD
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nonn,less
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AUTHOR
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Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Aug 17 2008
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EXTENSIONS
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Edited and corrected by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 21 2008
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