204288

Appears in sequences

• A convolution triangle of numbers obtained from A036070.at n=22A030526
• a(n) = sigma((10^n - 1)/9), where sigma(n) is the sum of positive divisors of n.at n=5A103759
• Triangle read by rows: the coefficients of the Mittag-Leffler polynomials.at n=50A137513
• Consider numbers n = concat(w,x,y,z) such that w*x*y*z | n. Leading zeros in x, y and z allowed. Sequence lists numbers that admit at least two such concatenations.at n=33A257172
• Triangle read by rows: T(n,k) is the number of permutations pi of [n] such that pi has k+1 valleys and s(pi) avoids the patterns 132 and 321, where s is West's stack-sorting map (0 <= k <= floor((n-1)/2)).at n=32A319030