22577

Appears in sequences

• Composite numbers n such that k! == 1 (mod n) for some k > 2.at n=22A049048
• A Wallis pair (x,y) satisfies sigma(x^2) = sigma(y^2); sequence gives y's for indecomposable Wallis pairs with x < y (ordered by values of x).at n=35A075769
• Number of distinct factorizations of 105*2^n.at n=16A093802
• Smallest k > 0 such that abs(S(k)P(k)-k) equals n, where S(k) is the sum and P(k) is the product of decimal digits of k or 0 if no such k exists.at n=37A114457
• Numbers k such that k and k^2 use only the digits 0, 2, 5, 7 and 9.at n=30A136917
• Smallest i such that prime(n) divides gcd(sigma(i), phi(i)) (cf. A009223).at n=15A222714
• Numbers of the form p*q, p and q prime with q=2p-3.at n=17A226755
• a(0) = 16, after which, if a(n-1) = product_{k >= 1} (p_k)^(c_k), then a(n) = (1/2) * (1 + product_{k >= 1} (p_{k+1})^(c_k)), where p_k indicates the k-th prime, A000040(k).at n=21A246344
• Expansion of Product_{k>=1} (1 + sigma(k)*x^k), where sigma(k) is the sum of the divisors of k (A000203).at n=18A316962