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Search: id:A050409
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| A050409 |
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Truncated square pyramid numbers: a(n)=sum(k^2,k=n..2*n). |
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+0
6
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| 0, 5, 29, 86, 190, 355, 595, 924, 1356, 1905, 2585, 3410, 4394, 5551, 6895, 8440, 10200, 12189, 14421, 16910, 19670, 22715, 26059, 29716, 33700, 38025, 42705, 47754, 53186, 59015, 65255, 71920, 79024, 86581, 94605, 103110, 112110, 121619
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=(1/6)*n*(n+1)*(14*n+1)
a(n) = A132121(n,4) for n>3. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 12 2007
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MAPLE
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seq(add((n+k)^2, k=0..n), n=0..37); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 01 2006
with(finance):seq(add(cashflows([n*k, k^2, 0], 3)*16, k=0..n), n=0..45); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 16 2008
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CROSSREFS
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Cf. A000330, A033994, A132124, A132112.
Sequence in context: A100559 A087348 A154412 this_sequence A111937 A139856 A097345
Adjacent sequences: A050406 A050407 A050408 this_sequence A050410 A050411 A050412
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 22 1999
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