OFFSET
1,1
COMMENTS
There is remote formal resemblance to amicable pairs.
LINKS
Klaus Brockhaus and Donovan Johnson, Table of n, a(n) for n = 1..1000 (first 126 terms from Klaus Brockhaus)
EXAMPLE
44 = 2*2*11 has sum of prime factors 15, which divides 44 + 1 = 45; 45 = 3*3*5 has sum of prime factors 11, which divides 44. Hence 44 is in the sequence.
PROG
(PARI) {m=4700000; s=2; for(n=2, m, f=factor(n+1); t=sum(j=1, matsize(f)[1], f[j, 1]*f[j, 2]); if((n+1)%s==0&&n%t==0, print1(n, ", ")); s=t)} /* Klaus Brockhaus, Jul 30 2007 */
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot, Jul 28 2007
EXTENSIONS
Edited and extended by Stefan Steinerberger and Klaus Brockhaus, Jul 30 2007
STATUS
approved