A359091 a(n) is the index of the smallest n-gonal number with binary weight n.

6, 13, 9, 10, 24, 58, 34, 55, 67, 151, 134, 187, 201, 691, 350, 623, 1082, 1870, 2302, 3171, 5017, 13863, 13230, 6663, 24357, 50397, 35604, 60347, 63810, 107019, 181517, 365595, 624858, 1345485, 1002585, 1969415, 1191179, 7651731, 4592173, 7279863, 7403686, 17923182

Offset: 3

Author

Ilya Gutkovskiy, Dec 16 2022

Keywords

• nonn
• base

Links

• Eric Weisstein's World of Mathematics, Polygonal Number
• Index entries for sequences related to binary expansion of n

Crossrefs

Cf. A000120, A211201, A231897, A359092.

Programs

Mathematica

p[n_, k_] := (n - 2)*k*(k - 1)/2 + k; a[n_] := Module[{k = 1}, While[DigitCount[p[n, k], 2, 1] != n, k++]; k]; Array[a, 30, 3] (* Amiram Eldar, Dec 17 2022 *)