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%I #18 Jun 22 2018 04:24:37
%S 1,5,51,99,155,209,2369,2569,2882,5745,15143,21691,34573,36566,40516,
%T 41237,65304,82718,101638,112305,185701,238302,247221,254865,291399,
%U 439104,445794,483107,532645,538531,570020,690238,698561,772485,805013
%N Numbers k such that sopf(k) = sopf(k^2 - 1), where sopf(k) = A008472(k).
%H Giovanni Resta, <a href="/A064019/b064019.txt">Table of n, a(n) for n = 1..1000</a> (first 100 terms from Harry J. Smith)
%o (PARI) sopf(n,s,fac,i)=fac=factor(n); for(i=1,matsize(fac)[1],s=s+fac[i,1]); return(s);
%o for(n=1,10^6, if(sopf(n)==sopf(n^2-1),print(n)))
%o (PARI) sopf(n)= { local(f,s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]); return(s) }
%o { n=0; for (m=1, 10^9, if (sopf(m)==sopf(m^2 - 1), write("b064019.txt", n++, " ", m); if (n==100, break)) ) } \\ _Harry J. Smith_, Sep 06 2009
%K nonn
%O 1,2
%A _Jason Earls_, Sep 07 2001
%E a(21)-a(35) from _Donovan Johnson_, Jun 15 2009
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