OFFSET
1,2
COMMENTS
Binomial transform of [1, 5, 6, 3, 0, 0, 0, ...].
Sum of the numbers in the top row and 1st column of an n X n square array whose elements are the numbers from 1..n^2, listed in increasing order by rows (see example). - Wesley Ivan Hurt, May 18 2021
LINKS
Andrew Howroyd, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = n*(n^2 + 3)/2 - 1.
EXAMPLE
From Wesley Ivan Hurt, May 18 2021: (Start)
Sum of the numbers in the top row and 1st column.
[1 2 3 4 5]
[1 2 3 4] [6 7 8 9 10]
[1 2 3] [5 6 7 8] [11 12 13 14 15]
[1 2] [4 5 6] [9 10 11 12] [16 17 18 19 20]
[1] [3 4] [7 8 9] [13 14 15 16] [21 22 23 24 25]
------------------------------------------------------------------------
n 1 2 3 4 5
------------------------------------------------------------------------
a(n) 1 6 17 37 69
------------------------------------------------------------------------
(End)
MATHEMATICA
Table[n*(n^2 + 3)/2 - 1, {n, 80}] (* Wesley Ivan Hurt, May 18 2021 *)
PROG
(PARI) a(n) = (n^3 + 3*n - 2)/2; \\ Andrew Howroyd, Apr 17 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Aug 10 2007
EXTENSIONS
Edited and terms a(13) and beyond from Andrew Howroyd, Apr 17 2021
STATUS
approved