30690

Appears in sequences

• a(n) = floor( n*(n-1)*(n-2)*(n-3)/32 ).at n=33A011942
• Numbers k whose decimal representation, read as a base-22 value and divided by k, yields an integer.at n=24A032575
• Nearest integer to log(n^n)^(1 + log(log(1 + n))).at n=29A062480
• Sigma unitary-sigma perfect numbers: numbers m which satisfy the following equation for some integer k: sigma(usigma(m)) = k*m where usigma(m) is sum of unitary divisors of m.at n=26A083288
• Numbers k such that 2*k+1, 4*k+1, 8*k+1 and 16*k+1 are primes.at n=27A124412
• Expansion of Product_{k>0} (1 - x^k)^(2^(k-1)) in powers of x.at n=21A200751
• G.f. satisfies: A(x) = 1 + x*A(x)^2 / (A(I*x) * A(-I*x)).at n=10A212527
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 481", based on the 5-celled von Neumann neighborhood.at n=34A272457
• Theta series of the 12-dimensional lattice of hyper-roots A_2(SU(3)).at n=10A290654
• a(n) is the position of the first occurrence of n^3 in the concatenation of the positive integers in decimal representation.at n=42A290787
• a(n) = 3*n*(2^n - 1).at n=10A317404
• a(n) = n*(n+1)*(n+3).at n=30A317637
• Number of order-4 ribbon tilings for a 4 X n strip.at n=10A364424
• Numbers m such that A188999(A034448(m)) = k*m for some k, where A034448 and A188999 are respectively the unitary and the bi-unitary sigma function.at n=37A369205
• Numbers x such that there exist three integers 0<x<=y, z>0 and w>0 such that sigma(x)^3 = sigma(y)^3 = x^3 + y^3 + z^3 + w^3.at n=43A385397
• a(n) is the least number x such that x^2 + 1 and 2^x + 1 are both divisible by A387595(n).at n=35A387642