133287

Appears in sequences

• Numbers k such that the k-th triangular number contains only digits {2,7,8}.at n=13A119179
• Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-1) + 2*b(n-2) - b(n-3), where a(0) = 1, a(1) = 3, a(2) = 5, b(0) = 2, b(1) = 4, b(2) = 6, and (a(n)) and (b(n)) are increasing complementary sequences.at n=20A295361
• Pythagorean triples (X, Y, Z) that are the componentwise products of 2 primitive Pythagorean triples (x,y,z) and (r,s,t), that is, X=x*r, Y=y*s, ordered by increasing Z.at n=29A340790