A046272 Largest prime substring in 6^n (0 if none).

0, 0, 3, 2, 29, 7, 5, 7993, 67961, 769, 604661, 2797, 78233, 1306069, 783641, 7018498457, 2821109, 692665944473, 66841, 609359, 4400629, 21936950640377, 16217038422671, 3022305360281, 73838133832161689, 992970137, 170581728179

Offset

0,3

Links

Harvey P. Dale, Table of n, a(n) for n = 0..100

Mathematica

Join[{0, 0}, Table[SelectFirst[Reverse[Union[FromDigits/@Flatten[Table[ Partition[ IntegerDigits[ 6^k], n, 1], {n, IntegerLength[6^k]-1}], 1]]], PrimeQ], {k, 2, 28}]] (* Harvey P. Dale, Mar 08 2023 *)

Crossrefs

Cf. A046264.

Sequence in context: A343130 A065353 A353757 * A054676 A181994 A350023

Adjacent sequences: A046269 A046270 A046271 * A046273 A046274 A046275

Keyword

nonn

Author

Patrick De Geest, Jun 15 1998

Status

approved