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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
OFFSET
1,3
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
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