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A068650
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Primes in which a string of 1's is sandwiched between two 3's.
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1
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313, 3111111111113, 311111111111113, 3111111111111111111111111111113, 311111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111113
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OFFSET
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1,1
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LINKS
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Table of n, a(n) for n=1..5.
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MAPLE
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a := 3:b := 1:i := 1:for n from 0 to 500 do c := a+10*(10^n-1)/9*b+10^(n+1)*a; if(isprime(c)) then d[i] := c; i := i+1; end if; end do:q := seq(d[j], j=1..i-1);
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CROSSREFS
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Cf. A068645, A068646, A068647, A068648, A068649.
Sequence in context: A210071 A083997 A164772 * A106156 A219961 A107116
Adjacent sequences: A068647 A068648 A068649 * A068651 A068652 A068653
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Feb 28 2002
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EXTENSIONS
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More terms from Sascha Kurz, Mar 19 2002
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STATUS
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approved
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