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A036931
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Smallest n-digit prime containing only digits 1 and 4, or 0 if no such prime exists.
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1
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0, 11, 0, 4111, 11411, 0, 1114111, 11111141, 0, 1111111411, 11111141411, 0, 1111111111441, 11111111111411, 0, 1111111111114441, 11111111111414411, 0, 1111111111111111111, 11111111111111414441, 0, 1111111111111111144141
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| For any positive integer k, a(3k) = 0 as any 3k-digit number containing only digits 1 or 4 or both has a digit-sum divisible by 3 and thus the number is divisible by 3. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Feb 08 2004
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FORMULA
| a(3k) = 0 and a(A004023(k)) = (10^A004023(k) - 1)/9 = A004022(k) for all positive integers k. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Feb 08 2004
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CROSSREFS
| Cf. A036229, A020452, A036304.
Cf. A004022 (repunit primes), A004023.
Sequence in context: A075361 A073864 A073865 * A165399 A157712 A158215
Adjacent sequences: A036928 A036929 A036930 * A036932 A036933 A036934
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KEYWORD
| nonn,base
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Jan 04 1999.
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EXTENSIONS
| More terms from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Feb 08 2004
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