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Search: id:A050410
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| A050410 |
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Truncated square pyramid numbers: a(n)=sum(k^2,k=n..2*n-1). |
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+0
3
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| 0, 1, 13, 50, 126, 255, 451, 728, 1100, 1581, 2185, 2926, 3818, 4875, 6111, 7540, 9176, 11033, 13125, 15466, 18070, 20951, 24123, 27600, 31396, 35525, 40001, 44838, 50050, 55651, 61655, 68076, 74928, 82225, 89981, 98210, 106926, 116143
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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a(n)=n*(7*n-1)*(2*n-1)/6.
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EXAMPLE
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1^2 + 1; 2^2 + 3^2 = 13; 3^2 + 4^2 + 5^2 = 50; ...
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MAPLE
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seq(add((n+k+1)^2, k=0..n), n=-1..36); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 01 2006
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PROGRAM
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(PARI) for(n=1, 100, print1(sum(i=0, n-1, (n+i)^2), ", "))
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CROSSREFS
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Cf. A072474.
Sequence in context: A044496 A009951 A074014 this_sequence A121991 A121990 A050491
Adjacent sequences: A050407 A050408 A050409 this_sequence A050411 A050412 A050413
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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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