|
|
A038544
|
|
a(n) = Sum_{i=0..10^n} i^3.
|
|
4
|
|
|
1, 3025, 25502500, 250500250000, 2500500025000000, 25000500002500000000, 250000500000250000000000, 2500000500000025000000000000, 25000000500000002500000000000000, 250000000500000000250000000000000000, 2500000000500000000025000000000000000000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
These terms k = x.y satisfy Diophantine equation x.y = (x+y)^2, when x and y have the same number of digits, "." means concatenation, and y may not begin with 0. So, this is a subsequence of A350870 and A238237. - Bernard Schott, Jan 20 2022
|
|
LINKS
|
|
|
FORMULA
|
a(n) = (10^n+1)^2 * 10^(2*n) / 4.
a(n) = A350869(n) + 10^(3*n). (End)
|
|
EXAMPLE
|
a(1) = Sum_{i=0..10} i^3 = (Sum_{i=0..10} i)^2 = 3025.
|
|
PROG
|
(PARI) sumcu(n) = for(x=0, n, y=10^x; z=y^2*(y+1)^2/4; (print1(z", "))) - Cino Hilliard, Jun 18 2007
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|