19840

Appears in sequences

• a(0) = 0; for n>0, a(n) = maximal number of regions into which space can be divided by n spheres.at n=40A046127
• a(n) = Sum_{i=0..n} T(i,n-i) where T is given by A047020.at n=16A047021
• Numbers k such that sigma (x) = k has exactly 11 solutions.at n=24A060678
• Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=3, I={-1,0,1}.at n=44A080002
• G.f. A(x) is defined as the limit A(x) = lim_{n->oo} F(n)^(1/2^(n-1)) where F(n) is defined by F(n) = F(n-1)^2 + (2*x)^(2^n-1) for n >= 1 with F(0) = 1.at n=11A101189
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+89)^2 = y^2.at n=10A129298
• Triangle read by rows: expansion of p(t) = (1 + t)^x/(1 + (1 + t)^n) with weight factor 2^(n+1)*n!.at n=25A137369
• Janet periodic table of the elements and structured hexagonal diamond numbers. a(n) = A166911(2*n) + A166911(2*n+1).at n=9A167471
• Numbers with prime signature {7,1,1}, i.e., of form p^7*q*r with p, q and r distinct primes.at n=25A179696
• Expansion of log(1/(1-Prime(x))) where Prime(x) = Sum{n>=1} A008578(n)*x^n.at n=9A180129
• Sequence related to the Hankel transform of A105523(n+5).at n=29A181474
• Number of (n+4)X7 binary arrays with every 5X5 subblock commuting with each horizontal and vertical neighbor 5X5 subblock.at n=4A186603
• Number of (n+4)X9 binary arrays with every 5X5 subblock commuting with each horizontal and vertical neighbor 5X5 subblock.at n=2A186605
• T(n,k)=Number of (n+4)X(k+4) binary arrays with every 5X5 subblock commuting with each horizontal and vertical neighbor 5X5 subblock.at n=23A186609
• T(n,k)=Number of (n+4)X(k+4) binary arrays with every 5X5 subblock commuting with each horizontal and vertical neighbor 5X5 subblock.at n=25A186609
• Composite numbers k such that k = (product of divisors of k) mod (sum of divisors of k).at n=45A187712
• a(n) = 2*n*(n+1)*(n+2)/3.at n=30A210440
• Sum of the divisors of n^3+1.at n=24A234645
• Number of length 3+2 0..n arrays with some pair in every consecutive three terms totalling exactly n.at n=14A245872
• a(n) = 4*n*(21*n - 26).at n=16A263229