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Search: id:A154813
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| A154813 |
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Primes n such that largest digit of n + smallest digit of prime(n) is a prime |
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+0
1
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| 2, 11, 41, 43, 59, 101, 127, 173, 211, 223, 241, 263, 307, 311, 313, 317, 389, 419, 487, 557, 601, 613, 617, 619, 647, 673, 677, 727, 739, 751, 757, 761, 827, 839, 853, 857, 883, 929, 953, 971, 1013, 1021, 1033, 1039, 1061, 1091, 1103, 1109, 1123, 1151, 1181
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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If 2(prime)=n and 3=prime(2), then 2+3=5(prime) and 2=a(1). If 11(prime)=n and 31=prime(11), then 1+1=2(prime) and 11=a(2). If 41(prime)=n and 179=prime(41), then 4+1=5(prime) and 41=a(3), etc.
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MAPLE
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nmax := proc (n) local nn: nn := convert(n, base, 10): max(seq(nn[j], j = 1 .. nops(nn))) end proc: nmin := proc (n) local nn: nn := convert(n, base, 10): min(seq(nn[j], j = 1 .. nops(nn))) end proc: a := proc (n) if isprime(n) = true and isprime(nmax(n)+nmin(ithprime(n))) = true then n else end if end proc: seq(a(n), n = 1 .. 1300); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 27 2009]
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CROSSREFS
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Sequence in context: A055329 A152895 A000822 this_sequence A080093 A078746 A066593
Adjacent sequences: A154810 A154811 A154812 this_sequence A154814 A154815 A154816
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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), Jan 15 2009, Jan 16 2009
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EXTENSIONS
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Corrected (added 101, 223, 853; removed 233, 239, 811) and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 27 2009
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