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A074344
a(1) = 8; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.
11
8, 9, 23, 51, 69, 81, 93, 129, 169, 179, 181, 273, 321, 323, 471, 493, 633, 689, 781, 933, 951, 969, 1229, 1309, 1509, 1707, 1821, 1863, 1913, 2169, 2337, 2433, 3259, 3513, 3681, 3921, 4431, 4611, 5043, 5091, 5361, 5409, 6231, 6471, 6999, 7757, 7963, 8283
OFFSET
1,1
MATHEMATICA
a[1] = 8; a[n_] := a[n] = Block[{k = a[n - 1] + 1 + Mod[a[n - 1], 2], c = IntegerDigits @ Table[ a[i], {i, n - 1}]}, While[ !PrimeQ[ FromDigits @ Flatten @ Append[c, IntegerDigits[k]]], k += 2]; k]; Table[ a[n], {n, 48}] (* Robert G. Wilson v *)
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Sep 23 2002
EXTENSIONS
Corrected and extended by Robert G. Wilson v, Aug 05 2005
STATUS
approved