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 A073045 Nonprime solutions to sopfr(n) = S(n), where sopfr(n) = A001414 and S(n) = A002034. 1

%I #12 Dec 05 2019 10:20:34

%S 4,9,25,27,49,121,125,169,289,343,361,529,625,841,961,1331,1369,1681,

%T 1849,2197,2209,2401,2809,3125,3481,3721,4489,4913,5041,5329,6241,

%U 6859,6889,7921,9409,10201,10609,11449,11881,12167,12769,14641,16129,16807

%N Nonprime solutions to sopfr(n) = S(n), where sopfr(n) = A001414 and S(n) = A002034.

%H Amiram Eldar, <a href="/A073045/b073045.txt">Table of n, a(n) for n = 1..10000</a>

%e sopfr(9) = S(9) = 6 and 6 is composite, so 9 is a term.

%o (PARI) {for(n=1,17000,if(!isprime(n),s=0; fac=factor(n); for(i=1,matsize(fac)[1],s=s+fac[i,1]*fac[i,2]); m=1; p=1; while(p%n>0,m++; p=p*m); if(s==m,print1(n,","))))}

%Y Cf. A001414, A002034, A074583.

%K nonn

%O 1,1

%A _Jason Earls_, Aug 24 2002

%E Edited and extended by _Klaus Brockhaus_, Aug 26 2002

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Last modified June 12 11:47 EDT 2024. Contains 373331 sequences. (Running on oeis4.)