A359317 a(n) is the smallest tetrahedral number with binary weight n.

0, 1, 10, 35, 120, 220, 455, 2024, 1771, 4060, 14190, 16215, 129766, 32509, 1414910, 1823471, 5159805, 8171255, 4192244, 24117100, 30865405, 334985911, 192937325, 1610599145, 1048440315, 4261347265, 4244012991, 63828916911, 213588635511, 133110357279

Offset

0,3

Links

Table of n, a(n) for n=0..29.

Eric Weisstein's World of Mathematics, Tetrahedral Number

Index entries for sequences related to binary expansion of n

Example

455 is the smallest tetrahedral number with binary weight 6 (455_10 = 111000111_2), so a(6) = 455.

Mathematica

seq[len_, nmax_] := Module[{s = Table[0, {len}], n = 0, c = 0, bw, t}, While[c < len && n < nmax, bw = DigitCount[t = n*(n+1)*(n+2)/6, 2, 1] + 1; If[bw <= len && s[[bw]] == 0, c++; s[[bw]] = t]; n++]; s]; seq[30, 10^6] (* Amiram Eldar, Dec 26 2022 *)

Crossrefs

Cf. A000120, A000292, A089999, A358931, A359318.

Sequence in context: A049736 A048507 A240267 * A221907 A195269 A070755

Adjacent sequences: A359314 A359315 A359316 * A359318 A359319 A359320

Keyword

nonn,base

Author

Ilya Gutkovskiy, Dec 25 2022

Status

approved