A357780 Primes p such that changing, in p, all 1's to 2's we get semiprimes and changing all 1's to 3's we get triprimes.

61, 199, 313, 421, 619, 661, 1033, 1163, 1217, 1283, 1301, 1361, 1567, 1613, 1721, 1723, 1759, 1987, 2179, 2341, 2617, 3011, 3163, 3217, 4211, 4519, 4621, 5107, 7417, 8117, 8123, 8317, 8521, 9199, 9319, 9721, 9817, 10037, 10093, 10099, 10139, 10163, 10211, 10243, 10567, 10589, 10601, 10687, 10781, 10837, 10957

Offset

1,1

Links

Table of n, a(n) for n=1..51.

Example

1217 (prime), 2227 = 17*131 (semiprime), 3237 = 3*13*83 (triprime).

Mathematica

s = {}; p = 2; Do[ p = NextPrime[p]; id = IntegerDigits[p]; id2 = id3 = id;
Do[If[id[[k]] == 1, id2[[k]] = 2; id3[[k]] = 3], {k, Length[id]}]; fd2 = FromDigits[id2];  fd3 = FromDigits[id3];  If[2 == PrimeOmega[fd2] && 3 == PrimeOmega[fd3], AppendTo[s, p]], {2000}]; s

Crossrefs

Cf. A000040, A001358, A014612.

Sequence in context: A139508 A364716 A245865 * A259410 A234925 A171585

Adjacent sequences: A357777 A357778 A357779 * A357781 A357782 A357783

Keyword

nonn,base

Author

Zak Seidov, Oct 14 2022

Status

approved