|
Search: id:A076461
|
|
|
| A076461 |
|
Sum of squares of numbers that can be written as t*n + u*(n+1) for nonnegative integers t,u in exactly two ways. |
|
+0
2
|
|
| 13, 571, 5306, 26470, 93455, 264313, 640276, 1383276, 2736465, 5047735, 8796238, 14621906, 23357971, 36066485, 54076840, 79027288, 112909461, 158115891, 217490530, 294382270, 392701463, 516979441, 672431036, 865020100
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
REFERENCES
|
Fred. Schuh, Vragen betreffende een onbepaalde vergelijking, Nieuw Tijdschrift voor Wiskunde, 52 (1964-1965) 193-198.
|
|
FORMULA
|
1/6*n*(n+1)*(25*n^4+26*n^3-6*n^2-7*n+1). G.f.: x*(61*x^4+864*x^3+1582*x^2+480*x+13)/((1+x)*(1-x)^7).
|
|
MAPLE
|
seq(1/6*n*(n+1)*(25*n^4+26*n^3-6*n^2-7*n+1), n=1..30);
|
|
CROSSREFS
|
Cf. A076389, A076460-A076465.
Sequence in context: A143601 A050286 A096761 this_sequence A142210 A109875 A067407
Adjacent sequences: A076458 A076459 A076460 this_sequence A076462 A076463 A076464
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Floor van Lamoen (fvlamoen(AT)hotmail.com), Oct 13 2002
|
|
|
Search completed in 0.002 seconds
|
