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A089999 Smallest triangular number with Hamming weight n (i.e., with exactly n 1's when written in binary). 5
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

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

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 *)

PROG

(Haskell)

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

CROSSREFS

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

Sequence in context: A229197 A188721 A212996 * A124397 A216324 A226319

Adjacent sequences:  A089996 A089997 A089998 * A090000 A090001 A090002

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Nov 20 2003

EXTENSIONS

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

Offset corrected by Donovan Johnson, May 01 2012

STATUS

approved

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Last modified May 23 05:03 EDT 2019. Contains 323508 sequences. (Running on oeis4.)