OFFSET
1,6
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
With[{lim = 10^13}, IntegerExponent[Select[Sort@ Flatten@Table[2^i*3^j - 1, {i, 0, Log2[lim]}, {j, 0, Log[3, lim/2^i]}], PrimeQ] + 1, 3]]
PROG
(PARI) lista(lim) = {my(s = List()); for(i = 0, logint(lim, 2), for(j = 0, logint(lim >> i, 3), listput(s, 2^i * 3^j - 1))); s = Set(s); for(i = 1, #s, if(isprime(s[i]), print1(valuation(s[i] + 1, 3), ", "))); }
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Oct 02 2024
STATUS
approved