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A054776
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3n*(3n-1)*(3n-2).
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2
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0, 6, 120, 504, 1320, 2730, 4896, 7980, 12144, 17550, 24360, 32736, 42840, 54834, 68880, 85140, 103776, 124950, 148824, 175560, 205320, 238266, 274560, 314364, 357840, 405150, 456456, 511920, 571704, 635970, 704880, 778596, 857280, 941094
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| Konrad Knopp, Theory and Application of Infinite Series, Dover, p. 268
L. B. W. Jolley, "Summation of Series", Dover Publications, 1961, p. 46
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LINKS
| Konrad Knopp, Theorie und Anwendung der unendlichen Reihen, Berlin, J. Springer, 1922. (Original german edition of "Theory and Application of Infinite Series")
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FORMULA
| a(n)=A007531(3n-2)= 6*A006566(n).
sum(n=1, inf, 1/a(n))=Pi*sqrt(3)/12-ln(3)/4 =0.178796768891527.. [Jolley eq. 250] - Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 05 2002
G.f.: 6x(1+16x+10x^2)/(1-x)^4.
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PROG
| (PARI) a(n)=3*n*(3*n-1)*(3*n-2)
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CROSSREFS
| Sequence in context: A001219 A076233 A066581 * A076231 A076234 A066289
Adjacent sequences: A054773 A054774 A054775 * A054777 A054778 A054779
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KEYWORD
| easy,nonn
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AUTHOR
| Henry Bottomley (se16(AT)btinternet.com), May 19 2000
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