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 A069604 a(1) = 1; for n>1, a(n) = smallest number with all odd digits giving a prime in concatenation with the previous terms. 6
 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; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS EXAMPLE a(5) = 1 and the number 113111 is a prime. MATHEMATICA 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[ CROSSREFS Cf. A033680, A074336, A092528, A069602. Sequence in context: A117526 A051498 A092528 * A098332 A096663 A302120 Adjacent sequences:  A069601 A069602 A069603 * A069605 A069606 A069607 KEYWORD nonn,base AUTHOR Amarnath Murthy, Mar 26 2002 EXTENSIONS Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003 STATUS approved

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Last modified August 4 07:32 EDT 2020. Contains 336201 sequences. (Running on oeis4.)