19689

Appears in sequences

• Numbers that are the sum of 9 nonzero 8th powers.at n=27A003387
• Numbers that are the sum of 7 positive 9th powers.at n=8A003396
• Numbers k such that phi(k) | sigma_8(k).at n=4A015766
• Number of binary words of length n with autocorrelation function 2^(n-1)+1.at n=16A045691
• n satisfying sigma(n+1) = sigma(n-1).at n=26A055574
• Numbers k such that sigma(k-1) divides sigma(k+1).at n=31A067130
• Smallest k > 6 such that sigma_n(k)/phi(k) is an integer.at n=7A078538
• a(n) = n^3 + 6.at n=27A084382
• Linear recurrence a(n) = a(n-3) + 2a(n-5), starting from all-one initial conditions.at n=40A133683
• 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, -1), (1, 0, 0), (1, 1, -1)}.at n=8A150115
• Triangle read by rows in which row n lists n terms, starting with n, such that the difference between successive terms is equal to n^4 - 1 = A123865(n).at n=39A162623
• Triangle read by rows in which row n lists n terms, starting with n^4 + n - 1, such that the difference between successive terms is equal to n^4 - 1 = A123865(n).at n=38A162624
• Partial sums of A018805.at n=44A177853
• Triangle T(n,m) = A060187(n+1,m+1) + 2*binomial(n,m) - 2, read by rows.at n=46A178122
• Triangle T(n,m) = A060187(n+1,m+1) + 2*binomial(n,m) - 2, read by rows.at n=53A178122
• Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).at n=27A223137
• Numbers k such that sigma(k+1) divides sigma(k-1).at n=27A227304
• Numbers m such that m - 3 divides m^m + 3.at n=19A252041
• a(n) = 6144*5^n - 12288*4^n + 7616*3^n - 1472*2^n + 41.at n=2A305863
• Array read by ascending antidiagonals: A(n, k) = n!*[x^n] Li(-k, 1 - exp(-4*x))/(4*sinh(x)), where Li(n, z) is the polylogarithm function.at n=23A345394