67656

Appears in sequences

• Numbers k such that k and k^2 use only the digits 3, 4, 5, 6 and 7.at n=14A137121
• Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = x + 4.at n=22A257606
• Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = x + 4.at n=26A257606
• a(n) is the number of five element sets of distinct integer-sided trapezoids whose base angles are 60 degrees that fill an equilateral triangular grid of side n units.at n=26A391498