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Search: id:A064444
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| 1, 4, 12, 28, 30, 52, 55, 65, 68, 76, 95, 145, 155, 185, 205, 822, 894, 2779, 2863, 8392, 23481, 24093, 24237, 64270, 174691, 174779, 1301989, 1302457, 3523478
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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sopf(n) = A008472(n) = sum of distinct prime factors of n.
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PROGRAM
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(PARI) pi(x, c=0) = forprime(p=2, x, c++); c sopf(n, fac) = fac=factor(n); sum(i=1, matsize(fac)[1], fac[i, 1]) j=[]; for(n=1, 25000, if(pi(n)==sopf(n), j=concat(j, n))); j
(PARI) sopf(n)= { local(f, s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]); return(s) } { n=0; for (m=1, 10^9, if (primepi(m)==sopf(m), write("b064444.txt", n++, " ", m); if (n==100, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 14 2009]
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CROSSREFS
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Cf. A008472, A000720.
Sequence in context: A007009 A104384 A013697 this_sequence A072182 A009906 A109629
Adjacent sequences: A064441 A064442 A064443 this_sequence A064445 A064446 A064447
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KEYWORD
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easy,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Oct 02 2001
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EXTENSIONS
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More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Oct 05 2001. No further terms < 800000.
a(27) - a(29) from Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 14 2009
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