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A069611 a(1) = 9; a(n) = smallest number such that the juxtaposition a(1)a(2)...a(n) is a prime. 21
9, 7, 1, 9, 17, 13, 33, 23, 7, 77, 31, 59, 51, 27, 7, 269, 439, 11, 429, 163, 39, 11, 463, 77, 63, 39, 33, 93, 21, 139, 53, 159, 49, 9, 291, 111, 21, 23, 349, 83, 3, 37, 11, 57, 21, 219, 507, 1233, 429, 147, 627, 127, 399, 27, 63, 423, 111, 633, 1391, 297, 831, 283 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

a(5) = 17 and the number 971917 is a prime.

MATHEMATICA

a[1] = 9; a[n_] := a[n] = Block[{k = 1, c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ !PrimeQ[ FromDigits @ Flatten @ Append[c, IntegerDigits[k]]], k += 2]; k]; Table[ a[n], {n, 63}] (from Robert G. Wilson v (rgwv(at)rgwv.com), Aug 05 2005)

CROSSREFS

Cf. A069602, A069604, A046259, A074345, A092528, A069603, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A111525.

Sequence in context: A106727 A094134 A154396 * A083995 A195357 A021511

Adjacent sequences:  A069608 A069609 A069610 * A069612 A069613 A069614

KEYWORD

nonn,base

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 26 2002

EXTENSIONS

More terms from Jason Earls (zevi_35711(AT)yahoo.com), Jun 13 2002

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.