21808

Appears in sequences

• dot product (n,n-1,...2,1).(3,4,...,n,1,2).at n=45A026054
• Number of step shifted (decimated) sequence structures using a maximum of five different symbols.at n=9A056394
• Number of n X n matrices with entries {0,1} that are diagonalizable over the real numbers.at n=3A091504
• Number of permutations of 1..n with displacements restricted to {-5,-4,-1,0,2,3}.at n=12A189591
• Numbers n such that the Collatz iterations for n and n + 1 have the same length (A078417) but do not meet a certain condition. (See comments.)at n=35A274410
• Sum of the asymmetry degrees of all compositions of n into parts congruent to 1 mod 3.at n=26A276061
• Number of partitions of n into 7 distinct and relatively prime parts.at n=52A339672
• Cogrowth sequence of the 12-element group A4 = <S,T | S^3, T^2, (ST)^3>.at n=18A377626