27686

Appears in sequences

• Numbers k such that sigma(k) = sigma(k+13).at n=10A015883
• Partial sums of Sum_{k=1..n} n/gcd(n,k), or partial sums of Sum_{d|n} d*phi(d) (see A057660).at n=47A174405
• a(n) is the number of inversions in all compositions of n.at n=13A189052
• Number of partitions of n where the difference between consecutive parts is at most 4.at n=43A238864
• Integers n not of form 3m+1 such that for any integer k>0, n*10^k-1 has a divisor in the set { 7, 11, 13, 37 }.at n=5A243974
• Number of (n+1) X (7+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.at n=1A250876
• T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.at n=29A250877
• Number of (2+1) X (n+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.at n=6A250879
• Convolution of A000041 and A000290.at n=18A360486