The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A071910 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A071910

a(n) = t(n)*t(n+1)*t(n+2), where t() are the triangular numbers.
(history; published version)

#27 by Alois P. Heinz at Wed Jan 19 21:58:24 EST 2022

STATUS

proposed

approved

#26 by Jon E. Schoenfield at Wed Jan 19 21:34:36 EST 2022

STATUS

editing

proposed

#25 by Jon E. Schoenfield at Wed Jan 19 21:34:35 EST 2022

COMMENTS

a(n) is also the number of three-dimensional cage assemblies such that the assembly is not a cube. See also A052149 for the 2 two-dimensional version and to A059827 for the non-exclusive version. - Alejandro Rodriguez, Oct 20 2020

STATUS

approved

editing

#24 by N. J. A. Sloane at Wed Oct 21 22:56:48 EDT 2020

STATUS

proposed

approved

#23 by Kevin Ryde at Tue Oct 20 22:43:00 EDT 2020

STATUS

editing

proposed

#22 by Kevin Ryde at Tue Oct 20 22:42:34 EDT 2020

LINKS

<a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1).

STATUS

proposed

editing

#21 by Wesley Ivan Hurt at Tue Oct 20 19:34:36 EDT 2020

STATUS

editing

proposed

#20 by Wesley Ivan Hurt at Tue Oct 20 19:34:22 EDT 2020

FORMULA

a(n) = ((n+1)*(n+2))^3/8 - sum(Sum_{i=1, ..n+1, } i^3) . - Jon Perry, Feb 13 2004

a(n) = C(2+n, n)*C(3+n, 1+n)*C(4+n, 2+n) . - Zerinvary Lajos, Jul 29 2005

STATUS

proposed

editing

#19 by Alejandro Rodriguez at Tue Oct 20 11:12:46 EDT 2020

STATUS

editing

proposed

#18 by Alejandro Rodriguez at Tue Oct 20 10:33:04 EDT 2020

COMMENTS

a(n) is also the number of three-dimensional cage assemblies such that the assembly is not a cube. Related See also A052149 for the 2 dimensional version and to A059827 for the non-exclusive version. - Alejandro Rodriguez, Oct 20 2020