274911

Appears in sequences

• Doubly triangular numbers: a(n) = n*(n+1)*(n^2+n+2)/8.at n=38A002817
• G.f. is the polynomial (1-x^3) * (1-x^6) * (1-x^9) * (1-x^12) * (1-x^15) * (1-x^18) * (1-x^21) * (1-x^24) * (1-x^27) * (1-x^30) * (1-x^33) * (1-x^36) * (1-x^39) / (1-x)^13.at n=9A162631
• Number of nX3 binary arrays with each sum of a(1..i,1..j) no greater than i*j/2.at n=6A183404
• T(n,k)=Number of nXk binary arrays with each sum of a(1..i,1..j) no greater than i*j/2.at n=38A183407
• T(n,k)=Number of nXk binary arrays with each sum of a(1..i,1..j) no greater than i*j/2.at n=42A183407
• Triangular numbers representable as x*y+x+y such that x and y are triangular numbers, x>=y>0.at n=37A259745
• Triangular numbers representable as x*y+x+y such that x and y are triangular numbers, x>=y>1.at n=31A259746