A155777 Primes with largest digit prime.

2, 3, 5, 7, 13, 17, 23, 31, 37, 47, 53, 67, 71, 73, 103, 107, 113, 127, 131, 137, 151, 157, 167, 173, 211, 223, 227, 233, 251, 257, 271, 277, 307, 311, 313, 317, 331, 337, 347, 353, 367, 373, 457, 467, 503, 521, 523, 541, 547, 557, 571, 577, 607, 617, 647, 673

Offset

1,1

Comments

Prime digits are 2, 3, 5 or 7.

Links

Table of n, a(n) for n=1..56.

Example

2=a(1), 3=a(2), 5=a(3), 7=a(4), 11(1 = 1 = nonprime), 13(1 < 3 = prime)=a(5), 17(1 < 7 = prime)=a(6), 19(1 < 9 = nonprime), 23(2 < 3 = prime)=a(7), etc.

Maple

ldig := proc(n) max(op(convert(n, base, 10))) ; end: for n from 1 to 800 do p := ithprime(n) ; if isprime(ldig(p)) then printf("%d, ", p) ; fi; od: # R. J. Mathar, Feb 13 2009

Crossrefs

Cf. A000040, A154390.

Sequence in context: A163998 A197299 A089438 * A262839 A234695 A067905

Adjacent sequences: A155774 A155775 A155776 * A155778 A155779 A155780

Keyword

nonn,base

Author

Juri-Stepan Gerasimov, Jan 27 2009

Status

approved