|
|
A185258
|
|
Side of triangle of the difference of pairs of triangular numbers whose sum and difference are triangular.
|
|
7
|
|
|
3, 11, 25, 20, 56, 73, 51, 42, 49, 183, 117, 406, 532, 602, 356, 325, 842, 144, 164, 900, 119, 1406, 1630, 1011, 1156, 935, 2050, 2000, 2222, 2541, 1690, 2488, 1981, 3699, 1308, 2924, 4371, 897, 311, 5113, 5735, 3783, 5549, 1807, 696, 5654, 6478
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
REFERENCES
|
Albert H. Beiler, Recreations in the theory of numbers, New York, Dover, (2nd ed.) 1966, p. 197, nr. 8.
|
|
LINKS
|
|
|
EXAMPLE
|
a(2) = 11, since the pair of triangular numbers 171 = 18*(18+1)/2 and 105 = 14*(14+1)/2 produce the sum 276 = 23*(23+1)/2 and the difference 66 = 11*(11+1)/2 which are both triangular numbers.
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|