A089338 Beginning with 3 the smallest number such that the concatenation a(n), a(n-1), ... a(2), a(1) is a prime.

3, 1, 1, 2, 1, 6, 11, 16, 11, 1, 8, 21, 13, 11, 34, 41, 12, 4, 66, 24, 15, 17, 4, 122, 70, 96, 33, 2, 43, 5, 3, 100, 44, 28, 23, 27, 12, 4, 113, 10, 3, 90, 9, 162, 15, 9, 69, 146, 9, 145, 74, 3, 42, 99, 31, 93, 35, 259, 53, 79, 14, 285, 84, 1, 36, 78, 147, 78, 66, 246, 155, 624

Offset

0,1

Links

Harvey P. Dale, Table of n, a(n) for n = 0..200

Example

3, 13, 113, 2113, 12113, 612113, ...etc. are primes.

Mathematica

nxt[{cnc_, a_}]:=Module[{k=1}, While[!PrimeQ[k*10^IntegerLength[ cnc]+ cnc], k++]; {k*10^IntegerLength[cnc]+cnc, k}]; NestList[nxt, {3, 3}, 80][[All, 2]] (* Harvey P. Dale, Jan 17 2022 *)

Crossrefs

Sequence in context: A270572 A095276 A246457 * A356400 A153066 A126209

Adjacent sequences: A089335 A089336 A089337 * A089339 A089340 A089341

Keyword

base,nonn

Author

Amarnath Murthy, Nov 04 2003

Extensions

More terms from Ray Chandler, Nov 07 2003

Status

approved