Decomposition of Central polygonal numbers
Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts.
Decomposition of Lower Wythoff sequence
Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2.
Decomposition of Triangular numbers
Triangular numbers: a(n) = C(n+1,2) = n(n+1)/2 = 0+1+2+...+n.
Decomposition of Squares
The squares: a(n) = n^2.
Decomposition of A000378
Numbers of the form x^2 + y^2 + z^2 (x, y, z >= 0).
Decomposition of A000379
A 2-way classification of integers: complement of A000028.
Decomposition of A000404
Numbers that are the sum of 2 nonzero squares. (seq not found)
Decomposition of A000408
Numbers that are the sum of 3 nonzero squares.
Decomposition of A000415
Numbers that are the sum of 2 but no fewer nonzero squares.