The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A162261 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A162261

a(n) = (2*n^3 + 5*n^2 - 7*n)/2.
(history; published version)

#27 by Michel Marcus at Sat Feb 25 05:24:47 EST 2023

STATUS

reviewed

approved

#26 by Joerg Arndt at Sat Feb 25 03:06:33 EST 2023

STATUS

proposed

reviewed

#25 by Amiram Eldar at Sat Feb 25 03:04:56 EST 2023

STATUS

editing

proposed

#24 by Amiram Eldar at Sat Feb 25 02:51:04 EST 2023

FORMULA

From Amiram Eldar, Feb 25 2023: (Start)

Sum_{n>=2} 1/a(n) = 8*log(2)/63 + 1166/19845.

Sum_{n>=2} (-1)^n/a(n) = (32*log(2) - 2*Pi - 3566/315)/63. (End)

STATUS

approved

editing

#23 by Charles R Greathouse IV at Thu Sep 08 08:45:46 EDT 2022

PROG

(MAGMAMagma) [(2*n^3 + 5*n^2 - 7*n)/2 : n in [1..50]]; // Wesley Ivan Hurt, May 07 2021

Discussion

Thu Sep 08

08:45

OEIS Server: https://oeis.org/edit/global/2944

#22 by Wesley Ivan Hurt at Fri May 07 13:48:05 EDT 2021

STATUS

editing

approved

#21 by Wesley Ivan Hurt at Fri May 07 13:47:40 EDT 2021

PROG

(MAGMA) [(2*n^3 + 5*n^2 - 7*n)/2 : n in [1..50]]; // Wesley Ivan Hurt, May 07 2021

STATUS

approved

editing

#20 by Alois P. Heinz at Thu Aug 30 23:17:17 EDT 2018

STATUS

proposed

approved

#19 by Jon E. Schoenfield at Thu Aug 30 23:14:57 EDT 2018

STATUS

editing

proposed

#18 by Jon E. Schoenfield at Thu Aug 30 23:14:54 EDT 2018

NAME

a(n) = (2n2*n^3 +5n 5*n^2 -7n 7*n)/2.

FORMULA

Row sums from A155724: a(n) = sumSum_{m=1..n} (2*m*n + m + n - 4, m=1..n).

From Vincenzo Librandi, Mar 04 2012: (Start)

G.f.: x^2*(11 - 5*x)/(1-x)^4. - Vincenzo Librandi, Mar 04 2012

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). - Vincenzo Librandi, Mar 04 2012(End)

MATHEMATICA

CoefficientList[Series[x*(11-5*x)/(1-x)^4, {x, 0, 40}], x] (* or *) LinearRecurrence[{4, -6, 4, -1}, {0, 11, 39, 90}, 50](* _Vincenzo Librandi, _, Mar 04 2012 *)

EXTENSIONS

New name from _Vincenzo Librandi, _, Mar 04 2012

STATUS

approved

editing