1,1

Table of n, a(n) for n=1..58.

2 is in the list since 1 + prime(2) = 4 and 1 + prime(3) = 6 are both products of 2 primes.

4 is in the list since 1 + prime(4) = 8 and 1 + prime(5) = 12 are both products of 3 primes.

Reap[Do[If[PrimeOmega[1 + Prime[n + 1]] == PrimeOmega[1 + Prime[n]], Sow[n]], {n, 200}]][[2, 1]]

Sequence in context: A018414 A002152 A163522 * A002466 A162842 A164901

Adjacent sequences: A255170 A255171 A255172 * A255174 A255175 A255176

nonn

Zak Seidov, Feb 15 2015

approved