|
|
A085036
|
|
a(n) = (5*n+2)*(5*n+7).
|
|
0
|
|
|
14, 84, 204, 374, 594, 864, 1184, 1554, 1974, 2444, 2964, 3534, 4154, 4824, 5544, 6314, 7134, 8004, 8924, 9894, 10914, 11984, 13104, 14274, 15494, 16764, 18084, 19454, 20874, 22344, 23864, 25434, 27054, 28724, 30444, 32214, 34034, 35904, 37824, 39794, 41814
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
1 = 2/7 + Sum(n=1,inf.,25/a(n)) = 2/7 + 25/84 + 25/204 + 25/374 + 25/594...+...; with partial sums: 2/7, 7/12, 12/17, 17/22...(5n+2)/(5n+7)...==>1
|
|
LINKS
|
|
|
FORMULA
|
25n^2 + 45n + 14.
|
|
MATHEMATICA
|
Table[(5n+2)(5n+7), {n, 0, 60}] (* or *) LinearRecurrence[{3, -3, 1}, {14, 84, 204}, 60] (* Harvey P. Dale, Jun 17 2023 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|