OFFSET
1,2
COMMENTS
The leading diagonal is A000292 (tetrahedral (or pyramidal) numbers: C(n+3,3) = (n+1)(n+2)(n+3)/6.)
The sequence contains very few duplicate terms. In the first 10000 terms, only 12 are duplicates and there are no terms that repeat more than two times. - Harvey P. Dale, Jun 10 2018
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..10000
EXAMPLE
1
5 4
18 17 10
50 48 37 20
115 110 93 67 35
...
MATHEMATICA
Module[{nn=10, r1, r2}, r1=Accumulate[Range[nn]]; r2=Total[r1]; Total/@ Flatten[ TakeList[#, Range[(Sqrt[8*Length[#]+1]-1)/2, 1, -1]]&/@TakeList[ Range[ r2], r1], 1]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jun 10 2018 *)
CROSSREFS
KEYWORD
AUTHOR
Amarnath Murthy, Dec 01 2004
EXTENSIONS
More terms from Ray Chandler, Dec 10 2004
STATUS
approved