|
Search: id:A076455
|
|
|
| A076455 |
|
Sum of numbers that can be written as t*n + u*(n+1) for nonnegative integers t,u in exactly two ways. |
|
+0
2
|
|
| 5, 57, 246, 710, 1635, 3255, 5852, 9756, 15345, 23045, 33330, 46722, 63791, 85155, 111480, 143480, 181917, 227601, 281390, 344190, 416955, 500687, 596436, 705300, 828425, 967005, 1122282, 1295546, 1488135, 1701435, 1936880, 2195952, 2480181
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
REFERENCES
|
Fred. Schuh, Vragen betreffende een onbepaalde vergelijking, Nieuw Tijdschrift voor Wiskunde, 52 (1964-1965) 193-198.
|
|
FORMULA
|
1/2*n*(n+1)*(4*n^2+2*n-1). G.f.: x*(11*x^2+32*x+5)/((1+x)*(1-x)^5).
|
|
MAPLE
|
seq(1/2*n*(n+1)*(4*n^2+2*n-1), n=1..40);
|
|
CROSSREFS
|
Cf. A002417, A076454-A076459.
Sequence in context: A132618 A060080 A163793 this_sequence A000362 A103047 A107339
Adjacent sequences: A076452 A076453 A076454 this_sequence A076456 A076457 A076458
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Floor van Lamoen (fvlamoen(AT)hotmail.com), Oct 13 2002
|
|
|
Search completed in 0.002 seconds
|
