20246

Appears in sequences

• Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 1), (0, 1), (1, 0)}.at n=13A151339
• a(n) = 0 + 1*2 + 3*4*5 + 6*7*8*9 + ... + ...*n.at n=13A227365
• Number of partitions of n such that the number of parts having multiplicity 1 is a part and the number of distinct parts is not a part.at n=42A241444
• Number of 4Xn 0..1 arrays with every element equal to 0, 1, 2 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=8A302417
• Numbers k for which R(k) + 3*10^floor(k/2) is prime, where R(k) = (10^k-1)/9 (repunit: A002275).at n=14A331866
• a(n) is the number of distinct radii of circles passing through at least three points in a square grid of n X n points.at n=19A357301
• Number of distinct characteristic polynomials for 2 X 2 matrices with entries from {0, 1, ..., n}.at n=23A366448