|
Search: id:A072502
|
|
|
| A072502 |
|
Numbers that are run sums (trapezoidal, the difference between two triangular numbers) in exactly 3 ways. |
|
+0
2
|
|
| 9, 18, 25, 36, 49, 50, 72, 98, 100, 121, 144, 169, 196, 200, 242, 288, 289, 338, 361, 392, 400, 484, 529, 576, 578, 676, 722, 784, 800, 841, 961, 968, 1058, 1152, 1156
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
LINKS
|
R. D. Knott Runsums
T. Verhoeff, Rectangular and Trapezoidal Arrangements, J. Integer Sequences, Vol. 2, 1999, #99.1.6.
|
|
EXAMPLE
|
a(1)=9 is the smallest number with 3 runsums: 2+3+4=4+5=9
|
|
CROSSREFS
|
Not to be confused with A069562. See A001227, A038547, A038550.
Adjacent sequences: A072499 A072500 A072501 this_sequence A072503 A072504 A072505
Sequence in context: A038837 A034046 A069562 this_sequence A102042 A121282 A110529
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Ron Knott (maths(AT)ronknott.com), Jan 27 2003
|
|
|
Search completed in 0.002 seconds
|
