a(n) is the least k such that the residues mod 3 of the primes prime(k), prime(k+1), ... comprise a string of n 2's followed by 1.

A391796

a(n) is the least k such that the residues mod 3 of the primes prime(k), prime(k+1), ... comprise a string of n 2's followed by 1.

Terms

    a(0) =3a(1) =9a(2) =15a(3) =54a(4) =290a(5) =987a(6) =4530a(7) =21481a(8) =58554a(9) =60967a(10) =136457a(11) =136456a(12) =673393a(13) =1254204a(14) =1254203a(15) =7709873a(16) =21357254a(17) =21357253a(18) =25813465a(19) =25813464a(20) =39500858a(21) =39500857a(22) =947438661a(23) =947438660a(24) =947438659a(25) =5703167679a(26) =5703167678a(27) =16976360924a(28) =68745739764a(29) =117327812949

External references