A111525 a(1) = 10; a(n) = smallest number such that the juxtaposition a(1)a(2)...a(n) is a prime.

10, 1, 3, 3, 3, 29, 1, 3, 3, 11, 9, 7, 23, 61, 11, 3, 91, 137, 7, 11, 31, 93, 17, 9, 273, 51, 397, 9, 99, 41, 111, 129, 111, 801, 109, 131, 297, 37, 621, 21, 807, 143, 87, 57, 231, 187, 53, 169, 77, 613, 867, 41, 199, 773, 523, 227, 27, 499, 171, 329, 67, 483, 393, 179

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..300

Mathematica

a[1] = 10; 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}]
nxt[{j_, a_}]:=Module[{k=1}, While[CompositeQ[j*10^IntegerLength[k]+k], k++]; {j*10^IntegerLength[k]+k, k}]; NestList[nxt, {10, 10}, 70][[;; , 2]] (* Harvey P. Dale, Sep 27 2025 *)

Crossrefs

Cf. A111524, A074346, A092528, A069603, A069605, A069606, A069607, A069608, A069609, A069610, A069611, A111525.

Sequence in context: A174209 A366165 A010181 * A138261 A068126 A156225

Adjacent sequences: A111522 A111523 A111524 * A111526 A111527 A111528

Keyword

base,nonn

Author

Amarnath Murthy, Jason Earls and Robert G. Wilson v, Aug 05 2005

Status

approved