OFFSET
1,1
FORMULA
It is conjectured that A000926 ends at 1848, in which case a(n) = 3*n^2+18*n-38 for all n >= 22. - Robert Israel, Sep 06 2016
MAPLE
N:= 10000: # to get positions of all 3*n^2 <= N
B:= sort(convert({seq(seq(seq(i*j + j*k + i*k, i=1..min(j-1, (N-j*k)/(j+k))), j=2..min(k-1, (N-k)/(1+k))), k=3..(N-2)/3)}, list)):
count:= 1:
for n from 1 to floor(sqrt(N/3)) do
if member(3*n^2, B, A[count]) then count:= count+1 fi
od:
seq(A[i], i=1..count-1); # Robert Israel, Sep 06 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms and a(4)-a(7) corrected by Gionata Neri, Sep 06 2016
STATUS
approved