Left- or right-truncatable primes in base 7.
2, 3, 5, 17, 19, 23, 31, 37, 41, 47, 137, 139, 163, 167, 223, 227, 233, 263, 293, 311, 313, 317, 331, 823, 853, 919, 977, 997, 1171, 1511, 1567, 1637, 1847, 2053, 2179, 2221, 2281, 2351, 2371, 2389, 5779, 6841, 6983, 10427, 10457, 10601, 10973, 11171, 11657
1
These numbers must be converted to base 7 and then truncated. For instance, the number 137 is 254(7).
T. D. Noe, Plot of 140 terms
T. D. Noe, Table of 140 terms
See references in A137812.
(Mma) b = 7; Clear[s]; n = 0; s[n] = Prime[Range[PrimePi[b-1]]]; While[cnt = 0; lst = Reap[Do[k = s[n][[i]]; Do[p = j*b^(n+1) + k; If[PrimeQ[p], Sow[p]; cnt++], {j, b-1}]; Do[p = b*k + j; If[PrimeQ[p], Sow[p]; cnt++], {j, b-1}], {i, Length[s[n]]}]]; cnt > 0, n++; s[n] = Union[lst[[2,1]]]]; t = s[0]; Do[t = Join[t, s[i]], {i, n}]; t
Cf. A137812 (base 10), S000910-S000916 (bases 9 to 3), S000917.
nonn,base,full
T. D. Noe, Jun 21 2016