OFFSET
1,1
LINKS
Harry J. Smith and Donovan Johnson, Table of n, a(n) for n = 1..100 (first 39 terms from Harry J. Smith)
PROG
(PARI) for(n=1, 30000000, if(eulerphi(n)==sigma(n)-sigma(n+1), print1(n, ", ")))
(PARI) { n=-1; t=0; for (m=1, 10^9, s=t; t=sigma(m + 1); if (eulerphi(m)==s - t, write("b063943.txt", n++, " ", m); if (n==38, break)) ) } [Harry J. Smith, Sep 03 2009]
CROSSREFS
KEYWORD
nonn
AUTHOR
Jason Earls, Sep 01 2001
EXTENSIONS
More terms from Rick L. Shepherd, Apr 06 2002
Offset corrected by Donovan Johnson, Feb 25 2013
STATUS
approved