20070

Appears in sequences

• 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), (0, 0, 1), (0, 1, 0), (1, 1, -1)}.at n=9A149880
• Numbers n such that prime(n) and phi(n) have the same decimal digits.at n=41A243462
• Number of (n+2) X (1+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.at n=7A252221
• T(n,k)=Number of (n+2)X(k+2) 0..2 arrays with every 3X3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.at n=28A252228
• T(n,k)=Number of (n+2)X(k+2) 0..2 arrays with every 3X3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4.at n=35A252228
• Let s denote the sum of the abundant numbers in the aliquot parts of x. Sequence lists numbers x such that sigma(s) = usigma(x), where usigma(x) is the sum of the unitary divisors of x (A034448).at n=8A258135
• Expansion of Product_{k>=0} ((1+x^(3*k+1))/(1-x^(3*k+1)))^3.at n=16A261651
• a(n) is the total number of elements in all sum-free subsets of {1,...,n}.at n=17A288888
• Bemirp gaps: differences between consecutive bemirps.at n=18A333648
• 4*a(n) is the maximum possible determinant of a 3 X 3 matrix whose entries are 9 consecutive primes starting with prime(n).at n=11A340923
• a(n) = Sum_{x_1|n, x_2|n, x_3|n, x_4|n} gcd(x_1,x_2,x_3,x_4).at n=47A344138
• a(n) = Sum_{k=1..prime(n)-1} floor(k^5/prime(n)).at n=4A361559
• a(n) = Sum_{k=0..floor(n/2)} binomial(n+k-1,k) * binomial(3*k,n-2*k).at n=9A389293
• Triangle read by rows: T(n,k) is the number of sets of noncrossing paths of size k whose nodes are a subset of n nodes arranged in a circle with one node paths allowed, 0 <= k <= n.at n=62A390897