A064522 For an integer n with prime factorization p1*p2*p3* ... *pn let n* = (p1-1)*(p2-1)*(p3-1)* ... *(pn-1) (A003958); sequence gives n such that n is divisible by n*.

1, 2, 4, 6, 8, 12, 16, 20, 24, 32, 36, 40, 48, 64, 72, 80, 84, 96, 120, 128, 144, 160, 168, 192, 216, 240, 256, 272, 288, 312, 320, 336, 384, 400, 432, 440, 480, 504, 512, 544, 576, 624, 640, 672, 720, 768, 800, 864, 880, 960, 1008, 1024, 1088, 1152, 1248, 1280

Offset: 1

Author

Vladeta Jovovic, Oct 07 2001

Keywords

• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A064476, A003958.

Programs

PARI

nsm(n)= { local(f,p=1); f=factor(n); for(i=1, matsize(f)[1], p*=(f[i, 1] - 1)^f[i, 2]); return(p) } { n=0; for (m=1, 10^9, if (m%nsm(m) == 0, write("b064522.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 17 2009