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A155777 Primes with largest digit prime. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Prime digits are 2, 3, 5 or 7.
LINKS
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
Sequence in context: A163998 A197299 A089438 * A262839 A234695 A067905
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)