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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
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
Sequence in context: A057626 A201310 A324272 * A172136 A248172 A064501
KEYWORD
nonn
AUTHOR
Jason Earls, Sep 05 2001
STATUS
approved