A064465 Numbers k such that A048138(k) = A034444(k).

5, 7, 13, 16, 19, 31, 36, 40, 41, 43, 49, 50, 53, 61, 74, 82, 84, 89, 92, 94, 102, 103, 107, 109, 113, 130, 138, 140, 149, 151, 154, 158, 169, 181, 182, 197, 199, 217, 229, 233, 239, 241, 243, 257, 266, 271, 293, 331, 349, 361, 383, 389, 409, 419, 421, 439, 463

Offset: 1

Author

Jason Earls, Oct 03 2001

Keywords

• easy
• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A034444, A048138.

Programs

PARI

f(n) = s=0; for(x=1,n^2, if(sigma(x)-x-1==n,s++)); s ud(n) = 2^omega(n); j=[]; for(n=1,150, if(f(n)==ud(n),j=concat(j,n))); j

PARI

f(n)= { local(s=0); for(x=1, n^2, if(sigma(x) - x - 1==n, s++)); return(s) } ud(n)= { 2^omega(n) } { n=0; for (m=1, 10^9, if (f(m)==ud(m), write("b064465.txt", n++, " ", m); if (n==100, break)) ) } \\ Harry J. Smith, Sep 15 2009

Extensions

More terms from Klaus Brockhaus, Oct 03 2001