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A089999 Smallest triangular number with Hamming weight n (i.e., with exactly n 1's when written in binary). 9
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
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
Sequence in context: A188721 A367324 A212996 * A124397 A216324 A226319
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 March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)