40740

Appears in sequences

• Number of 5-ary search trees on n keys.at n=15A019499
• Number of nonsquare divisors of n!.at n=19A056596
• Triangle formed from coefficients of the polynomials p(1)=x, p(n+1) = (n + x*(n+1))*p(n) + x*x*(d/dx)p(n).at n=23A075856
• Triangle read by rows: rows = inverse binomial transforms of columns of A309220.at n=31A118980
• Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=9.at n=33A135194
• An eighth of the product of three integers surrounding the (n+1)-st prime, minus half of the product of the 3 numbers surrounding n+1.at n=18A141535
• A partition product of Stirling_1 type [parameter k = 4] with biggest-part statistic (triangle read by rows).at n=23A157394
• Coefficients of a set of polynomials associated with the derivatives of x^x.at n=22A185164
• Number of n X 7 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=5A208378
• Number of 6 X n 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 1 0 1 vertically.at n=6A208382
• Triangle read by rows: T(0,0)=1; T(m,0)=0; otherwise T(m,n) = (m-1)*T(m-1,n)+(m-1+n)*T(m-1,n-1).at n=31A239098
• Number of length n+6 0..4 arrays with no seven consecutive terms having the maximum of any three terms equal to the minimum of the remaining four terms.at n=0A249879
• T(n,k)=Number of length n+6 0..k arrays with no seven consecutive terms having the maximum of any three terms equal to the minimum of the remaining four terms.at n=6A249883
• Number of length 1+6 0..n arrays with no seven consecutive terms having the maximum of any three terms equal to the minimum of the remaining four terms.at n=3A249884
• Numbers n such that sigma(n) = m*sigma(n+2) with some m > 1.at n=4A260988
• Partition the decimal expansion of Pi into non-overlapping strings of length 10: 3141592653, 5897932384,..; a(n) is the position of the strings where digits are different from each other.at n=13A329368
• a(n) = Sum_{k=1..n} sigma_2( n/gcd(k,n) ).at n=39A372226
• Numbers k such that the powerful part of the sum of divisors of k (A387726) is greater than or equal to k, and sigma(k) is not itself a powerful number.at n=33A387729