A239616 Numbers that end in the trivial cycle (0) under the rule: next term = product of the last four digits of the concatenated preceding terms.

0, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 16, 18, 20, 22, 23, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 63, 64, 65, 66, 67, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105

Offset

1,2

Links

Table of n, a(n) for n=1..89.

Prog

(PARI) is(n) = !A238984(99, n, 4) \\ Here, the somewhat arbitrary value 99 (number of iterations before checking for 0) should be sufficiently large for small n, but might need to be increased for larger starting values n.

Crossrefs

Cf. A238984, A239419 (analog for k=3), A239721, A239722.

Sequence in context: A372317 A117923 A117924 * A231848 A200373 A140335

Adjacent sequences: A239613 A239614 A239615 * A239617 A239618 A239619

Keyword

nonn,base

Author

M. F. Hasler, Aug 01 2014

Status

approved