OFFSET
1,1
COMMENTS
Except for the first term, terms are primes of the form p+4 with p prime, i.e., the sequence is essentially A031505, A046132. In other words, the solutions to sigma(x) < x + 4 are 1,2,4 and the odd primes. - Ralf Stephan, Feb 09 2004
PROG
(PARI) isok(p) = isprime(p) && (p>4) && (sigma(p-4) < p); \\ Michel Marcus, Feb 15 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Benoit Cloitre, Feb 08 2002
EXTENSIONS
Edited by Charles R Greathouse IV, Mar 19 2010
STATUS
approved