123039

Appears in sequences

• a(n) = n*(2*n+1)^2.at n=31A084367
• Expansion of -x*(-1-x+x^2) / ( 1-2*x-3*x^2+x^3 ).at n=11A095125
• a(n) = Product_{i=0..2} (2^floor((n+i)/3)-1).at n=17A274626