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A051943 Truncated triangular pyramid numbers: a(n)=sum(k*(k+1)/2-45,k=9..n). 0
0, 10, 31, 64, 110, 170, 245, 336, 444, 570, 715, 880, 1066, 1274, 1505, 1760, 2040, 2346, 2679, 3040, 3430, 3850, 4301, 4784, 5300, 5850, 6435, 7056, 7714, 8410, 9145, 9920, 10736, 11594, 12495, 13440, 14430, 15466, 16549, 17680, 18860, 20090 (list; graph; refs; listen; history; internal format)
OFFSET

9,2

FORMULA

a(n)=1/6*(n+20)*(n-8)*(n-9)

CROSSREFS

A000292.

Sequence in context: A063154 A100500 A085473 * A059306 A192023 A163655

Adjacent sequences:  A051940 A051941 A051942 * A051944 A051945 A051946

KEYWORD

easy,nice,nonn

AUTHOR

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 21 1999

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.