| 1, 4, 12, 18, 24, 32, 56, 91, 78, 72, 144, 168, 112, 192, 360, 270, 234, 260, 360, 576, 384, 288, 672, 868, 434, 560, 960, 720, 720, 768, 992, 1488, 864, 864, 1872, 1482, 760, 1120, 2352, 1764, 1344, 1408, 1584, 2808, 1872, 1152, 2880, 3420, 1767, 2232
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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EXAMPLE
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a(4)=18 because sum of divisors of 4th triangular number(i.e. 10) is 1+2+5+10=18.
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MATHEMATICA
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t[n_]:=n*(n+1)/2; f[n_]:=Plus@@Divisors[t[n]]; lst={}; Do[AppendTo[lst, f[n]], {n, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 08 2009]
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CROSSREFS
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Adjacent sequences: A074282 A074283 A074284 this_sequence A074286 A074287 A074288
Sequence in context: A047958 A111371 A078514 this_sequence A057311 A063679 A075867
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KEYWORD
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nonn
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AUTHOR
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Shyam Sunder Gupta (guptass(AT)rediffmail.com), Sep 21 2002
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