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A069607 a(1) = 5; a(n) = smallest number such that the juxtaposition a(1)a(2)...a(n) is a prime. 20
5, 3, 23, 1, 3, 9, 21, 9, 21, 23, 43, 3, 23, 7, 21, 89, 37, 21, 137, 1, 119, 493, 143, 133, 483, 267, 179, 7, 333, 359, 439, 101, 33, 31, 533, 19, 63, 39, 333, 839, 63, 693, 423, 327, 73, 29, 39, 21, 517, 27, 99, 251, 7, 411, 243, 33, 149, 49, 227, 283, 303, 351, 303 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

a(5) = 3 and the number 532313 is a prime.

MATHEMATICA

a[1] = 5; 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, A046255, A074341, A092528, A069603, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A111525.

Sequence in context: A154825 A091593 A139699 * A128366 A083756 A146317

Adjacent sequences:  A069604 A069605 A069606 * A069608 A069609 A069610

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 14:07 EST 2012. Contains 205623 sequences.