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Search: id:A157158
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| A157158 |
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Primes where the first digit is equal to the largest digit. |
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+0
1
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| 2, 3, 5, 7, 11, 31, 41, 43, 53, 61, 71, 73, 83, 97, 101, 211, 311, 313, 331, 401, 421, 431, 433, 443, 503, 521, 523, 541, 601, 613, 631, 641, 643, 653, 661, 701, 727, 733, 743, 751, 757, 761, 773, 811, 821, 823, 827, 853, 857, 863, 877, 881, 883, 887, 907, 911
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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2(2=2), 3(3=3), 5(5=5), 7(7=7), 31(3=3>1), 41(4=4>1), 43(4=4>3), etc.
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MAPLE
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a := proc (n) local nn, nnn: nn := convert(ithprime(n), base, 10): nnn := seq(nn[j], j = 1 .. nops(nn)): if nn[nops(nn)] = max(nnn) then ithprime(n) else end if end proc: seq(a(n), n = 1 .. 200); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 02 2009]
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CROSSREFS
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Cf. A000040.
Sequence in context: A028912 A075236 A155081 this_sequence A155833 A028867 A104154
Adjacent sequences: A157155 A157156 A157157 this_sequence A157159 A157160 A157161
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KEYWORD
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nonn
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AUTHOR
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Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Feb 24 2009
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EXTENSIONS
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11, 313 etc. inserted by Emeric Deutsch (deutsch(AT)duke.poly.edu) and R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 26 2009
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