33915

Appears in sequences

• a(n) = 10*binomial(2*n + 1, n - 4)/(n + 6).at n=6A003519
• Odd integers m such that phi(m) | sigma(m).at n=17A015715
• Denominator of |Bernoulli(2n+2)| - |Bernoulli(2n)|.at n=8A029765
• In A015922, not in A033553.at n=39A033554
• a(n) = n*(n+1)*(5*n+1)/6.at n=33A033994
• Odd numbers with exactly 5 distinct prime factors.at n=8A046391
• Denominators of column 3 of table described in A051714/A051715.at n=16A051721
• Numbers k such that 3^k == -1 (mod k-1).at n=15A055686
• Numbers k such that usigma(k) = phi(k)*omega(k), where omega(k) is the number of distinct prime divisors of k.at n=19A063795
• Seventh column of Catalan triangle A009766.at n=9A064059
• Numbers k such that sigma(k) = bigomega(k) * phi(k).at n=15A067238
• Numbers k such that sigma(k) = phi(k*bigomega(k)).at n=14A068400
• Numbers k such that sigma(k) = phi(k)*omega(k).at n=8A073567
• Numbers k such that both k and 2*k are balanced numbers (A020492).at n=26A076375
• Squarefree balanced numbers (i.e., squarefree members of A020492).at n=44A078557
• Numbers n such that the middle coefficient of the cyclotomic polynomial Phi_n(x) has a value not obtained for any smaller n.at n=18A095877
• Odd squarefree abundant numbers.at n=8A112643
• Triangle read by rows: T(n,k) is the number of Grand Dyck paths of semilength n that cross downwards the x-axis k times. (A Grand Dyck path of semilength n is a path in the half-plane x>=0, starting at (0,0), ending at (2n,0) and consisting of steps u=(1,1) and d=(1,-1)).at n=32A118919
• a(1) = 1; a(2) = 0; a(3) = 0; a(4) = 0; a(5) = 0; a(6) = 0; a(7) = 0; a(8) = 0; a(9) = 0; a(10) = 0; a(n) = a(n - 1) + 9a(n - 2) - 8a(n - 3) - 28a(n - 4) + 21a(n - 5) + 35a(n - 6) - 20a(n - 7) - 15a(n - 8) + 5a(n - 9) + a(n - 10) for n >= 11.at n=22A122602
• Odd infinitary abundant numbers.at n=23A127666