OFFSET
1,1
COMMENTS
Numbers of the form m*(6*k^2 + 6*k*m + 2*m^2 - 6*k - 3*m + 1)/6 for some m>=4 and k>=1. - Robert Israel, May 06 2019
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
30=1^2+2^2+3^2+4^2, 54=2^2+3^2+4^2+5^2, 55=1^2+2^2+3^2+4^2+5^2, ...
MAPLE
N:= 1000: # to get all terms <= N
Res:= NULL:
for m from 4 while m*(m+1)*(2*m+1)/6 <= N do
for k from 1 do
v:= m*(6*k^2 + 6*k*m + 2*m^2 - 6*k - 3*m + 1)/6;
if v > N then break fi;
Res:= Res, v;
od od:
sort(convert({Res}, list)); Robert Israel, May 06 2019
MATHEMATICA
max=60^2; lst={}; Do[z=n^2+(n+1)^2+(n+2)^2; Do[z+=(n+x)^2; If[z>max, Break[]]; AppendTo[lst, z], {x, 3, Sqrt[max]/2}], {n, Sqrt[max]/2}]; Union[lst]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Mar 06 2010
EXTENSIONS
Edited by Robert Israel, May 06 2019
STATUS
approved