A060787 a(n) = 18*(n - 2)*(2*n - 5).

0, 18, 108, 270, 504, 810, 1188, 1638, 2160, 2754, 3420, 4158, 4968, 5850, 6804, 7830, 8928, 10098, 11340, 12654, 14040, 15498, 17028, 18630, 20304, 22050, 23868, 25758, 27720, 29754, 31860, 34038, 36288, 38610, 41004, 43470, 46008, 48618, 51300, 54054, 56880, 59778

Offset

2,2

Comments

Except for first term Engel expansion of cosh(1/3); cf. A006784 for Engel expansion definition. - Benoit Cloitre, Mar 03 2002

References

L. Berzolari, Allgemeine Theorie der Höheren Ebenen Algebraischen Kurven, Encyclopädie der Mathematischen Wissenschaften mit Einschluss ihrer Anwendungen. Band III_2. Heft 3, Leipzig: B. G. Teubner, 1906. p. 341.

H. Brocard and T. Lemoyne, Courbes géométriques remarquables (courbes spéciales) Planes et Gauches. Tome I, Paris: Albert Blanchard, 1967 [First publ. 1919]; see p. 135.

Links

Harry J. Smith, Table of n, a(n) for n = 2..1000

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Formula

G.f.: 18*x^3*(1 + 3*x)/(1 - x)^3. - Colin Barker, Feb 29 2012

Prog

(PARI) a(n) = 18*(n - 2)*(2*n - 5) \\ Harry J. Smith, Jul 11 2009

Crossrefs

Sequence in context: A225219 A002165 A008654 * A019584 A356420 A289393

Adjacent sequences: A060784 A060785 A060786 * A060788 A060789 A060790

Keyword

nonn,easy

Author

Antreas P. Hatzipolakis (xpolakis(AT)otenet.gr), Apr 28 2001

Status

approved