21831

Appears in sequences

• a(n) = Sum_{i=0..n} Sum_{j=0..n} A026637(i,j).at n=13A026646
• Zeckendorf expansion of n: repeatedly subtract the largest Fibonacci number you can until nothing remains. Big-endian concatenation of decimals.at n=33A035514
• Rhombi (in 3 different orientations) in a rhombus with 60-degree acute angles.at n=37A052153
• 33-gonal numbers: n(31n-29)/2.at n=38A098923
• Number of nX7 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=3A302366
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=48A302367
• Number of 4Xn 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=6A302370
• Triangle read by rows: T(n, k) = qStirling1(n, k, q) for q = 2, with 0 <= k <= n.at n=23A333142