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A062332
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Primes starting and ending with 1.
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9
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11, 101, 131, 151, 181, 191, 1021, 1031, 1051, 1061, 1091, 1151, 1171, 1181, 1201, 1231, 1291, 1301, 1321, 1361, 1381, 1451, 1471, 1481, 1511, 1531, 1571, 1601, 1621, 1721, 1741, 1801, 1811, 1831, 1861, 1871, 1901, 1931, 1951, 10061, 10091, 10111, 10141
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OFFSET
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1,1
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COMMENTS
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Complement of A208261 (nonprime numbers with all divisors starting and ending with digit 1) with respect to A208262 (numbers with all divisors starting and ending with digit 1). - Jaroslav Krizek, Mar 04 2012
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LINKS
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FORMULA
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EXAMPLE
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102701 is a member as it is a prime and the first and the last digits are both 1.
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MATHEMATICA
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fl1Q[n_]:=Module[{idn=IntegerDigits[n]}, First[idn]==Last[idn]==1]; Select[ Prime[Range[1300]], fl1Q] (* Harvey P. Dale, Apr 30 2012 *)
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PROG
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(PARI) { n=-1; t=log(10); forprime (p=2, 5*10^5, if ((p-10*(p\10)) == 1 && (p\10^(log(p)\t)) == 1, write("b062332.txt", n++, " ", p); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 05 2009
(Haskell)
a062332 n = a062332_list !! (n-1)
a062332_list = filter ((== 1) . a010051') a208259_list
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CROSSREFS
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Cf. A208259 (Numbers starting and ending with digit 1).
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 29 2001
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STATUS
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approved
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