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Search: id:A089999
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| A089999 |
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Smallest triangular number with Hamming weight n (i.e. with exactly n 1's when written in binary). |
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+0
4
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| 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; listen)
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OFFSET
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1,3
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COMMENT
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A000120(a(n)) = n.
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MATHEMATICA
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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 (from Robert G. Wilson v Dec 03 2003)
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CROSSREFS
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Cf. A000217, A089998, A061712, A090002.
Sequence in context: A002857 A024011 A052445 this_sequence A124397 A043081 A091675
Adjacent sequences: A089996 A089997 A089998 this_sequence A090000 A090001 A090002
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KEYWORD
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nonn,base
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 20 2003
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 03 2003
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