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Search: id:A007586
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| A007586 |
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11-gonal (or hendecagonal) pyramidal numbers: n(n+1)(3n-2)/2.
(Formerly M4835)
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+0
7
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| 0, 1, 12, 42, 100, 195, 336, 532, 792, 1125, 1540, 2046, 2652, 3367, 4200, 5160, 6256, 7497, 8892, 10450, 12180, 14091, 16192, 18492, 21000, 23725, 26676, 29862, 33292, 36975, 40920, 45136, 49632, 54417, 59500
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 194.
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FORMULA
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G.f.: x*(1+8*x)/(1-x)^4.
Starting with "1", equals binomial transform of [1, 11, 19, 9, 0, 0, 0,...]. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Nov 02 2007
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MAPLE
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restart: a:=n->sum(sum(k, j=3..n), k=0..n): seq(a(n), n=1..53):b:=n->sum(sum(n, j=1..n), k=0..n): seq(a(n), n=1..53):c:=b+a:seq(c(n), n=0..35); [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 24 2008]
a:=n->add(binomial(n, 2)+add(n, j=3..n), j=2..n):seq(a(n), n=1..40); [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 27 2008]
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CROSSREFS
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Cf. A051682.
Cf. A093644 ((9, 1) Pascal, column m=3).
Sequence in context: A005901 A090554 A009948 this_sequence A066972 A122973 A074356
Adjacent sequences: A007583 A007584 A007585 this_sequence A007587 A007588 A007589
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas, R. K. Guy.
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