A211201 Smallest m such that (sum of binary digits of m*(m+1)/2) = n.

0, 1, 2, 6, 5, 10, 19, 22, 37, 77, 108, 165, 90, 313, 461, 620, 1252, 1957, 2610, 3237, 5654, 7797, 9818, 15797, 22245, 34725, 56723, 92634, 122330, 178540, 226838, 507571, 454045, 490426, 1480005, 2284378, 1482842, 2965594, 5931098, 10218573, 11096982, 21793257, 31317157

Offset

0,3

Links

Donovan Johnson, Table of n, a(n) for n = 0..71 (terms < 2*10^12)

Formula

A050493(a(n)) = n and A050493(m) <> n for m < a(n).

Prog

(Haskell)
import Data.List (elemIndex)
import Data.Maybe (fromJust)
a211201 = fromJust . (`elemIndex` a050493_list)
(PARI) a(n) = my(m=0); while (hammingweight(m*(m+1)/2) != n, m++); m; \\ Michel Marcus, Jan 27 2022

Crossrefs

Cf. A089999, A050493, A000217, A000120.

Sequence in context: A195488 A092744 A077174 * A359035 A179627 A193977

Adjacent sequences: A211198 A211199 A211200 * A211202 A211203 A211204

Keyword

nonn,base

Author

Reinhard Zumkeller, Feb 04 2013

Status

approved