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Search: id:A069490
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| A069490 |
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Primes > 1000 in which every substring of lengths 2 and 3 are also prime. |
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+0
5
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| 1373, 3137, 3797, 6131, 6173, 6197, 9719, 11311, 11317, 17971, 31379, 61379, 71971, 113131, 113173, 113797, 131311, 131317, 131797, 179719, 317971, 431311, 431797, 617971, 1131131, 1131379, 1311311, 1313797, 1317971, 3131137, 3131311
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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11317 is a term as the substrings of length 2 i.e. 11,13,31,17 and the three substrings of length 3 i.e. 113,131 and 317 are all prime.
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MATHEMATICA
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Do[ If[ Union[ PrimeQ[ Map[ FromDigits, Partition[ IntegerDigits[ Prime[n]], 2, 1]]]] == Union[ PrimeQ[ Map[ FromDigits, Partition[ IntegerDigits[ Prime[n]], 3, 1]]]] == {True}, Print[ Prime[n]]], {n, PrimePi[1000] + 1, 10^5}]
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CROSSREFS
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Cf. A069488 and A069489.
Sequence in context: A155925 A060981 A140125 this_sequence A045131 A056049 A056087
Adjacent sequences: A069487 A069488 A069489 this_sequence A069491 A069492 A069493
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 30 2002
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EXTENSIONS
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Edited, corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 12 2002
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