19125
domain: N
Appears in sequences
- Geometric mean of phi(n) and sigma(n) is an integer, n odd.at n=33A015705
- Number of bicentered 5-valent trees with n nodes.at n=17A036649
- Numbers whose base-2 representation has exactly 13 runs.at n=22A043580
- To obtain a(n+1), add the square of the n-th partial sum to the n-th partial sum of the squares, then divide this result by a(n), for all n >= 0, with a(0)=1.at n=9A088016
- Integers k such that nextprime(k^5) - prevprime(k^5) = 4.at n=15A090123
- Main diagonal of A090806.at n=14A108469
- Sixth-order spt function.at n=11A221144
- Number of ballot sequences of length n having exactly ten descents.at n=2A241803
- Sum_{i=1..n} Sum_{j=1..n} (i OR j), where OR is the binary logical OR operator.at n=29A258438
- Row 5 of A277710: Positions of 5's in A264977; positions of 10's in A277330.at n=37A277715
- Numbers m such that m = p^2 + k^2, with p > 0, where p = A007954(m) = the product of digits of m.at n=21A334557
- Nonsquarefree numbers k such that A003415(k) divides A276086(k), where A003415 is the arithmetic derivative, and A276086 is the primorial base exp-function.at n=32A371085
- a(n) = Sum_{k=0..floor(n/3)} binomial(3*n-2*k,n-3*k).at n=6A371754