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A063968 Numbers k such that sopf(k) = sopf(k+2), where sopf(k) = A008472(k). 2
2, 340, 845, 950, 1340, 3724, 5694, 6102, 7657, 8991, 9331, 9709, 10323, 11388, 11390, 12460, 15870, 18912, 19778, 20882, 21715, 24732, 26978, 29052, 29632, 32428, 33596, 35028, 38178, 42718, 43068, 45750, 46102, 50396, 53251, 61408 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 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);

j=[]; for(n=1, 100000, if(sopf(n)==sopf(n+2), 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; r=sopf(1); s=sopf(2); for (m=1, 10^9, t=sopf(m + 2); if(r==t, write("b063968.txt", n++, " ", m); if (n==1000, break)); r=s; s=t ) } \\ Harry J. Smith, Sep 04 2009

CROSSREFS

Cf. A008472, A006145.

Sequence in context: A057626 A201310 A324272 * A172136 A248172 A064501

Adjacent sequences:  A063965 A063966 A063967 * A063969 A063970 A063971

KEYWORD

nonn

AUTHOR

Jason Earls, Sep 05 2001

STATUS

approved

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Last modified February 18 15:30 EST 2020. Contains 332019 sequences. (Running on oeis4.)