cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

4, 9, 25, 27, 49, 121, 125, 169, 289, 343, 361, 529, 625, 841, 961, 1331, 1369, 1681, 1849, 2197, 2209, 2401, 2809, 3125, 3481, 3721, 4489, 4913, 5041, 5329, 6241, 6859, 6889, 7921, 9409, 10201, 10609, 11449, 11881, 12167, 12769, 14641, 16129, 16807
Offset: 1

Views

Author

Jason Earls, Aug 24 2002

Keywords

Examples

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

Crossrefs

Programs

  • 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,","))))}

Extensions

Edited and extended by Klaus Brockhaus, Aug 26 2002