A089999 Smallest triangular number with Hamming weight n (i.e., with exactly n 1's when written in binary).

0, 1, 3, 21, 15, 55, 190, 253, 703, 3003, 5886, 13695, 4095, 49141, 106491, 192510, 784378, 1915903, 3407355, 5240703, 15986685, 30400503, 48201471, 124780503, 247431135, 602930175, 1608777726, 4290575295, 7482375615, 15938355070

Offset: 0

Author

Reinhard Zumkeller, Nov 20 2003

Keywords

• nonn
• base

Comments

A000120(a(n)) = n.

a(n) = A000217(A211201(n)). - Reinhard Zumkeller, Mar 18 2013

Links

• Donovan Johnson, Table of n, a(n) for n = 0..60

Crossrefs

Cf. A211201, A000217, A089998, A061712, A090002.

Programs

Haskell

a089999 = a000217 . a211201  -- Reinhard Zumkeller, Mar 18 2013

Mathematica

a = Table[0, {30}]; Do[t = n(n + 1)/2; c = Count[ IntegerDigits[t, 2], 1]; If[ a[[c + 1]] == 0, a[[c + 1]] = t], {n, 1, 10^8}]; a (* Robert G. Wilson v, Dec 03 2003 *)

Extensions

More terms from Robert G. Wilson v, Dec 03 2003

Offset corrected by Donovan Johnson, May 01 2012