31421

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 1/3 of the elements are <= (n-1)/3.at n=17A048006
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/3 of the elements are <= (n-2)/3.at n=17A048017
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/3 of the elements are <= (n-3)/3.at n=17A048028
• a(n) = Sum_{k=0..floor(n/4)} C(n-3*k,k+1).at n=31A098578
• Apply partial sum operator 5 times to partition numbers.at n=13A120477
• Sum of squares of five consecutive primes.at n=19A131686
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 0), (1, 0, -1), (1, 0, 1)}.at n=10A148692
• Number of length n left factors of Dyck paths having no UDUD's; here U=(1,1) and D=(1,-1).at n=19A191792
• The Wiener index of the graph obtained by applying Mycielski's construction to a benzenoid consisting of a linear chain of n hexagons.at n=17A228597
• a(n) = n*prime(prime(n)) - prime(n).at n=35A230285
• Number of unlabeled rooted trees with n nodes such that the minimal outdegree of inner nodes equals 4.at n=28A244458
• Number of subsets of {1..n} containing n such that it is possible to choose a different binary index of each element.at n=31A370639