OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..63
EXAMPLE
a(4) = 97 is in the sequence because 97 is prime, the sum of digits of 97 is 9+7 = 16 and the sum of primes dividing 98=2*7*7 is 2+7+7 = 16.
MAPLE
sod:= n -> convert(convert(n, base, 10), `+`):
spf:= proc(n) local t; add(t[1]*t[2], t=ifactors(n)[2]) end proc:
select(p -> sod(p) = spf(p+1), [seq(ithprime(i), i=1..10^5)]);
PROG
(PARI) isok(p) = if (isprime(p), my(f=factor(p+1)); sumdigits(p) == f[, 1]~*f[, 2]); \\ Michel Marcus, Dec 18 2020
CROSSREFS
KEYWORD
nonn,base
AUTHOR
J. M. Bergot and Robert Israel, Dec 18 2020
STATUS
approved