153520

Appears in sequences

• Numbers k having at least two complementary pairs of divisors (q, p) and (p', q') such that k = p*q = p'*q' where the decimal digits of p' are the 9's complement of the decimal digits of p and the decimal digits of q' are the 9's complement of the decimal digits of q.at n=26A226587
• Irregular triangle read by rows: T(n, k) = number of ways to tile an n X n X n triangular area with k 2 X 2 X 2 triangular tiles and an appropriate number (= n^2-4*k) of 1 X 1 X 1 tiles.at n=46A286436
• On a spirally numbered square grid, with labels starting at 0, this is the number of the last cell that a (1,n) leaper reaches before getting trapped, or -1 if it never gets trapped.at n=19A323472
• Lower (1/2)-midsequence of Fibonacci numbers (A000045) and tribonacci numbers (A000213); see Comments.at n=22A390348
• Upper (1/2)-midsequence of Fibonacci numbers (A000045) and tribonacci numbers (A000213); see Comments.at n=22A390349