24448

Appears in sequences

• a(n) = [ (3rd elementary symmetric function of P(n))/(first elementary symmetric function of P(n)) ], where P(n) = {first n+2 primes}.at n=14A024453
• Geometric mean of digits = 4 and digits are in nondecreasing order.at n=13A069518
• G.f.: Product((1+x^i)/(1-x^i),i=1..n-1)/(1-x^n), with n = 8.at n=27A091779
• Number of occurrences of pattern 2-1 after n iterations of morphism A007413.at n=7A093357
• a(n) = p*(p+(2n-1))/2, where p = A096822(n) is the smallest primes of form 2^x-(2n-1).at n=32A096823
• Numbers k such that phi(k) + sigma(k) = (5/2)*k.at n=5A115747
• Row sums of triangle A135858.at n=29A135859
• Abundant numbers n such that n/(sigma(n)-2n) is an integer.at n=29A153501
• Abundant numbers n for which the abundance d = sigma(n) - 2*n is a proper divisor, that is, 0 < d < n and d | n.at n=27A181595
• Near-perfect numbers (A181595) of the form 2^(t-1)*(2^t-2^k-1), where 2^t-2^k-1 is prime, k>=1, t>k.at n=12A181701
• Number of (n+2) X 9 binary arrays with every 3 X 3 subblock commuting with each horizontal and vertical neighbor 3 X 3 subblock.at n=15A190031
• Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and positive determinant.at n=6A211148
• Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 22", based on the 5-celled von Neumann neighborhood.at n=7A269716
• Numbers n whose abundance is 64: sigma(n) - 2n = 64.at n=5A275996
• Decimal representation of the diagonal from the origin to the corner of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 49", based on the 5-celled von Neumann neighborhood.at n=14A285559
• Number of regions in a regular drawing of the complete bipartite graph K_{n,n}.at n=19A290131
• Bi-unitary near-perfect numbers: bi-unitary abundant numbers k such that the abundance d = bsigma(k) - 2*k is a bi-unitary divisor of k, where bsigma(k) is the sum of bi-unitary divisors of k (A188999).at n=36A303359
• Primitive practical numbers of the form 2^i * prime(k).at n=41A308710
• Sequence shifts left four places under Weigh transform with a(n) = signum(n) for n<4.at n=31A316076
• Three-column array pPT read by rows: subsequence of primitive Pythagorean triples (x, y, z) with x = A153893^2 - A000079^2, y = 2*A153893*A000079, z = A153893^2 + A000079^2, ordered by increasing z.at n=19A334638