Henry Potts-Rubin - cp's OEIS frontend

User: Henry Potts-Rubin

Henry Potts-Rubin has authored 2 sequences.

A316315 Numbers k such that the product of digits of k is a power of 12.

1, 11, 26, 34, 43, 62, 111, 126, 134, 143, 162, 216, 223, 232, 261, 289, 298, 314, 322, 341, 368, 386, 413, 431, 449, 466, 494, 612, 621, 638, 646, 664, 683, 829, 836, 863, 892, 928, 944, 982, 1111, 1126, 1134, 1143, 1162, 1216, 1223, 1232, 1261, 1289, 1298

Offset: 1

Isaac Weiss and Henry Potts-Rubin, Jun 29 2018

			466 is in the sequence because 4*6*6 = 144 = 12^2.

Alois P. Heinz, Table of n, a(n) for n = 1..64235

Cf. A284375, A002275, A028846, A174813, A284323, A276037, A276038, A276039, A284324, A284295, A328560.

FromDigits /@ Select[Join @@ Map[Tuples[{1, 2, 3, 4, 6, 8, 9}, #] &, Range@4], IntegerQ@Log[12, Times @@ #] &]

Two duplicate terms removed by Alois P. Heinz, Oct 20 2019

A316270 Number of tricolorable prime knots with n minimal crossings.

Original entry on oeis.org

0, 0, 0, 1, 0, 0, 1, 2, 8, 21, 62, 210, 779, 3799

Offset: 0

Isaac Weiss, Henry Potts-Rubin, Jun 28 2018

			For n = 7, a(7)=2 because only 2 prime knots with minimal crossing number 7 are tricolorable: 7_4 and 7_7.

Y. Kiriu and K. Ouchi, Various Functions of Mathematica about the Knot Theory, 2007. [dead link]
C. Livingston and A. H. Moore, KnotInfo: Table of Knot Invariants.

Cf. A002863 (Number of prime knots with n crossings).

a(11)-a(13) using KnotInfo (taking the knots with determinant a multiple of 3) added by Andrey Zabolotskiy, Apr 29 2024

cp's OEIS Frontend

User: Henry Potts-Rubin

A316315 Numbers k such that the product of digits of k is a power of 12.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

Mathematica

Extensions