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Search: id:A109353
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| A109353 |
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a(n) is the sum of the distinct prime divisors of A024619(n). |
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+0
2
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| 5, 7, 5, 9, 8, 5, 7, 10, 13, 5, 15, 9, 10, 14, 19, 12, 5, 21, 16, 7, 12, 13, 8, 25, 5, 7, 20, 15, 5, 16, 9, 22, 31, 10, 33, 10, 18, 16, 19, 26, 14, 5, 39, 8, 21, 18, 18, 7, 43, 12, 22, 45, 32, 13, 10, 20, 25, 34, 49, 24, 5, 9, 14, 7, 22, 15, 15, 55, 5, 18, 40, 9, 24, 28, 31, 16, 61, 24
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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a(3)=5 because the 3rd non-prime-power is 12 and its prime factors sum to 5.
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PROGRAM
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(PARI) distinct(n) = \sum the distinct prime factors of n { local(a, x, m, ln, s); for(m=2, n, s=0; a=ifactord(m); ln=length(a); if(ln > 1, for(x=1, ln, s+=a[x]; ); print1(s", ") ) ) } ifactord(n, m=0) = \distinct prime factors of n { local(f, j, k, flist); flist=[]; f=Vec(factor(n, m)); for(j=1, length(f[1]), flist = concat(flist, f[1][j]) ); return(flist) }
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CROSSREFS
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Cf. A024619.
Sequence in context: A090987 A065746 A065478 this_sequence A121595 A125294 A139428
Adjacent sequences: A109350 A109351 A109352 this_sequence A109354 A109355 A109356
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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), Aug 21 2005
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EXTENSIONS
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Edited by Don Reble (djr(AT)nk.ca), Jul 23 2006
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