A392104 a(n) = prime(A391796(n)).

5, 23, 47, 251, 1889, 7793, 43451, 243161, 726893, 759821, 1820123, 1820111, 10141499, 19725479, 19725473, 136209239, 400414127, 400414121, 489144659, 489144599, 766319201, 766319189, 21549657581, 21549657551, 21549657539, 140432294399, 140432294381, 437339303279

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Mathematica

t = Table[Mod[Prime[nn], 3], {nn, 10^8}]; (* A039701 *)
u = Map[SequencePosition[t, Flatten[Join[{ConstantArray[2, #], 1}]], 1] &, Range[21]]
Prime[Table[First[Flatten[u[[n]]]], {n, 1, 21}]]
(* Peter J. C. Moses, Dec 11 2025 *)

Prog

(Python)
from sympy import nextprime, prime
from itertools import count, islice
def agen(NN=10000): # generator of terms for n <= NN
    n, pk, residues = 1, 1, "X"*NN
    for k in count(1):
        pk = nextprime(pk)
        resk = pk%3
        if resk == 1:
            while residues.endswith("2"*n) and n <= NN:
                yield prime(k-n)
                n += 1
        residues = residues[1:] + str(resk)
print(list(islice(agen(), 12))) # Michael S. Branicky, Jan 11 2026

Crossrefs

Cf. A391796, A391807.

Sequence in context: A107011 A031387 A057622 * A055626 A127200 A147113

Adjacent sequences: A392101 A392102 A392103 * A392105 A392106 A392107

Keyword

nonn

Author

Clark Kimberling, Jan 08 2026

Extensions

a(22)-a(27) from Michael S. Branicky, Jan 11 2026

a(28) from Jinyuan Wang, Jan 16 2026

Status

approved