A393300 a(1) = 0; for n > 1, a(n) is the smallest unused number k such that k! contains a(1), a(2), ..., a(n-1) as substrings.

0, 5, 7, 17, 21, 36, 61, 73, 82, 87, 89, 97, 136, 151, 166, 196, 201, 260, 389, 491, 514, 515, 591, 640, 682, 703, 713, 717, 722, 741, 791, 798, 853, 869, 883, 913, 928, 934, 978, 979, 982, 1003, 1025, 1296, 1474, 1619, 2014, 2257, 2416, 2716, 2954, 3027, 3257

Offset

1,2

Links

Scott R. Shannon, Table of n, a(n) for n = 1..190

Formula

a(n) > a(n-1).

Example

a(5) = 21 as 21! = 51090942171709440000 which contains a(1) = 0, a(2) = 5, a(3) = 7, a(4) = 17 as substrings.

Crossrefs

Cf. A000142, A393301, A385673, A346120, A392010, A392011.

Sequence in context: A331892 A331893 A331895 * A164120 A342799 A043879

Adjacent sequences: A393297 A393298 A393299 * A393301 A393302 A393303

Keyword

nonn,base

Author

Scott R. Shannon, Feb 10 2026

Status

approved