OFFSET
1,1
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1)=65: 64=2^6 (1 distinct prime 2), 65=5*13 (2 distinct primes 5 and 13, 66=2*3*11 (3 distinct primes 2, 3, and 11).
MATHEMATICA
seq[nmax_] := Module[{om}, om[n_] := om[n] = PrimeNu[n]; Select[Range[2, nmax], om[# - 1] == om[#] - 1 && om[# + 1] == om[#] + 1 &]]; seq[2500] (* Amiram Eldar, Sep 19 2024 *)
PROG
(PARI) for(n=3, 2100, my(om=omega(n)); if(omega(n-1)==om-1&&omega(n+1)==om+1, print1(n, ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Mar 07 2021
STATUS
approved