126701

Appears in sequences

• a(n) = sum of squares of first n positive integers congruent to 1 mod 4.at n=28A024381
• Triangle T(n, k) = Numbers of inequivalent (mod D_3) ways to place k points on a triangular grid of side n so that no three of them are vertices of an equilateral triangle with sides parallel to the grid. Triangle read by rows.at n=40A243207
• Composite numbers k of the form 4u+1 for which the odd part of phi(k) divides k-1.at n=39A339870
• a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/2)} (-2)^k * a(k) * a(n-2*k-1).at n=20A352009