A064010 - OEIS

A064010

Numbers k such that sopf(k) = d(k) where d(k) = A001223(k) and sopf(k) = A008472(k).

2, 64, 135, 154, 168, 256, 350, 512, 539, 1029, 1350, 1875, 2106, 2268, 2646, 2673, 2736, 2976, 4375, 6000, 6076, 6517, 6880, 7680, 9680, 10092, 10584, 14000, 14406, 14580, 14976, 17500, 18522, 20412, 26000, 26068, 26112, 26620, 27216, 28812

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OFFSET

1,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..2000 (first 150 terms from Harry J. Smith)

PROG

(PARI) sopf(n, s, fac, i)=fac=factor(n); for(i=1, matsize(fac)[1], s=s+fac[i, 1]); return(s);

d(n) = prime(n+1)-prime(n);

j=[]; for(n=1, 50000, if(sopf(n)==d(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) }

d(n)= { prime(n + 1) - prime(n) }

{ default(primelimit, 13500000); n=0; for (m=1, 10^9, if (sopf(m)==d(m), write("b064010.txt", n++, " ", m); if (n==150, break)) ) } \\ Harry J. Smith, Sep 05 2009

CROSSREFS

Cf. A001223, A008472.

Sequence in context: A330059 A004853 A249073 * A120829 A226397 A264481

Adjacent sequences: A064007 A064008 A064009 * A064011 A064012 A064013

KEYWORD

easy,nonn

AUTHOR

Jason Earls, Sep 07 2001

STATUS

approved