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Search: id:A155777
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| A155777 |
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Primes with largest digit prime. |
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+0
1
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| 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; listen)
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OFFSET
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1,1
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COMMENT
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Prime digits are 2, 3, 5 or 7.
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EXAMPLE
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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.
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MAPLE
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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: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 13 2009]
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CROSSREFS
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Cf. A000040.
Sequence in context: A094317 A074834 A089438 this_sequence A067905 A042993 A033664
Adjacent sequences: A155774 A155775 A155776 this_sequence A155778 A155779 A155780
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KEYWORD
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nonn,base
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AUTHOR
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Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jan 27 2009
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