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Search: id:A076971
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| A076971 |
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a(1) = 1, a(n+1)= smallest triangular number greater than the n-th partial sum. |
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+0
2
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| 1, 3, 6, 15, 28, 55, 120, 231, 465, 946, 1891, 3828, 7626, 15225, 30628, 61075, 122265, 244650, 489555, 979300, 1959210, 3918600, 7838820, 15677200, 31359240, 62714400, 125429041, 250868800, 501732003, 1003497600, 2006959690
(list; graph; listen)
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OFFSET
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1,2
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MAPLE
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a[1] := 1:a[2] := 3:for n from 3 to 145 do a[n] := sum(a[i], i=1..n-1); a[n] := ceil(evalf(-1/2+1/2*sqrt(1+8*a[n])+10^(-19), 100)):a[n] := a[n]*(a[n]+1)/2: od:seq(a[k], k=1..145);
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CROSSREFS
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Cf. A076972.
Sequence in context: A056278 A000740 A069712 this_sequence A103529 A034953 A086737
Adjacent sequences: A076968 A076969 A076970 this_sequence A076972 A076973 A076974
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 21 2002
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EXTENSIONS
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More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Jan 22 2003
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