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Search: id:A069604
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| A069604 |
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a(1) = 1; for n>1, a(n) = smallest number with all odd digits giving a prime in concatenation with the previous terms. |
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+0
7
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| 1, 1, 3, 11, 1, 3, 3, 53, 13, 39, 9, 3, 399, 11, 9, 133, 3, 11, 51, 111, 13, 53, 31, 3, 173, 1, 317, 519, 579, 1, 573, 357, 5111, 39, 51, 73, 3317, 1977, 5173, 579, 357, 359, 9, 57, 3991, 959, 951, 7, 111, 1959, 39, 191, 3357, 3151, 3137, 577, 117, 1353, 951, 153, 99
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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a(5) = 1 and the number 113111 is a prime.
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Block[{k = 1, c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ Union[ Mod[ IntegerDigits[k], 2]] != {1} || !PrimeQ[
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CROSSREFS
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Cf. A033680, A074336, A092528, A069602.
Sequence in context: A117526 A051498 A092528 this_sequence A098332 A096663 A133369
Adjacent sequences: A069601 A069602 A069603 this_sequence A069605 A069606 A069607
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KEYWORD
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nonn,base
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 26 2002
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EXTENSIONS
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Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003
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