OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
13 is a term because 14 and 15 each have 4 divisors: {1, 2, 7, 14} and {1, 3, 5, 15}.
MATHEMATICA
Select[Range[3200], PrimeQ[#] && DivisorSigma[0, # + 1] == DivisorSigma[0, # + 2] &] (* Amiram Eldar, Jan 26 2020 *)
PROG
(PARI) isok(n) = isprime(n) && (numdiv(n+1) == numdiv(n+2)); \\ Michel Marcus, Oct 10 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jul 29 2006
STATUS
approved