

A335799


a(n) is the least number k such that 3^k2 and 3^k+2 are the product of n prime factors counted with multiplicity.


0




OFFSET

1,1


COMMENTS

a(9) >= 521, a(10) >= 368, a(11) >= 339, a(12) >= 551.  Chai Wah Wu, Sep 23 2020


LINKS



EXAMPLE

a(1) = 2 because 3^22 = 7 and 3^2+2 = 11 are both prime.


MATHEMATICA

m = 6; s = Table[0, {m}]; c = 0; k = 1; While[c < m, n = PrimeOmega[3^k  2]; If[n <= m && s[[n]] == 0, n2 = PrimeOmega[3^k + 2]; If[n2 == n, s[[n]] = k; c++]]; k++]; s (* Amiram Eldar, Sep 18 2020 *)


PROG

(PARI) a(n) = {my(k=1); while((bigomega(3^k2) != n)  (bigomega(3^k+2) != n), k++); k; } \\ Michel Marcus, Sep 14 2020


CROSSREFS



KEYWORD

nonn,more


AUTHOR



EXTENSIONS



STATUS

approved



