21233664

Appears in sequences

• Product k^(2^(k-1)), k = 1..n.at n=3A005832
• a(1) = 1, a(n+1)= a(n)*(n+1) divided by the largest prime divisor of n+1.at n=23A076928
• Smallest number beginning with 2 and having exactly n prime divisors counted with multiplicity.at n=21A106422
• Coefficient of q^n in (1-q)^4/(1-4q); dimensions of the enveloping algebra of the derived free Lie algebra on 4 letters.at n=13A118265
• Squares which are divisible by the product of their digits.at n=15A118548
• a(n) = n^2*4^n.at n=9A128782
• a(n) = the smallest positive integer with exactly the same number of divisors as in the first n positive integers combined.at n=26A160996
• Quartic recurrence sequence a(0) = 1, a(n) = n*a(n-1)^4.at n=4A164334
• a(n) = n^2 if n is odd, n^2*2^(n-2) if n is even.at n=18A168251
• Numbers expressible as A*B^A in two or more different ways, with A, B > 1.at n=14A171606
• Numbers k such that tau(sigma(k)) = rad(k).at n=33A173581
• a(n) = Product_{k=1..n} b(k,n), where b(k,n) is the largest positive integer that, when written in binary, occurs as a substring in both binary k and binary n.at n=17A175490
• Numbers which can be written using their digits in order and only multiplication and squaring operators.at n=22A194766
• Numbers that can be written using its own digits in order and using multiplication and cubing operators.at n=6A195671
• a(0) = 1, a(n) = a(n - 1) * (length of binary representation of n).at n=15A214936
• Smallest number of the form 11*m+1 with exactly n prime factors, counted with multiplicity.at n=22A230123
• Irregular triangle T(n,m), denominators of coefficients in a power/Fourier series expansion of the plane pendulum's exact time dependence.at n=19A274131
• a(n) = 4^(2*n) * (n!)^3 * (n+1)!.at n=3A280100
• Terms of A025487 from which the distance to the next larger prime is a composite number.at n=13A329894
• Positions of records in A050377, number of ways to factor n into "Fermi-Dirac primes" (A050376).at n=23A330687