20754

Appears in sequences

• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 16.at n=17A031694
• Convolution of A000108 (Catalan numbers) with A040075.at n=4A045505
• A triangle related to A000108 (Catalan) and A000302 (powers of 4).at n=50A046527
• a(n) = K_4(n) = Sum_{k>=0} A090285(4,k)*2^k*binomial(n,k). a(n) = 2*(n^4+14*n^3+62*n^2+91*n+21)/3.at n=10A090296
• a(1) = 3, a(2) = 4. a(n) = (largest composite which occurs earlier in sequence) + (largest prime which occurs earlier in sequence).at n=32A120365
• a(n) = 256*n^2 + 2*n.at n=8A158230
• a(n) = 324*n^2 + 18.at n=8A158590
• Smallest number k such that k^n is the sum of numbers in a twin prime pair.at n=12A195336
• Numbers k which use half of the ten digits such that they have at least one factorization k=p*q that uses remaining half of the digits that are not in k.at n=7A195814
• Number of ascent sequences avoiding the pattern 120.at n=10A202061
• Numbers n such that n contains exactly 5 digits, all distinct, and n^2 contains exactly 9 distinct digits.at n=15A204691
• Numbers n = p * q, where n, p, and q together contain all 10 digits at least once.at n=8A253172
• Values n, where n = p * q, and n, p, and q together contain all 10 digits at least once, and no digit is in more than one of n, p or q.at n=7A253173
• Numbers k such that 7*10^k + 57 is prime.at n=30A270974
• Number of ways to choose a strict rooted partition of each part in a constant rooted partition of n.at n=45A301768
• Number of integer partitions (of any nonnegative integer) whose sum minus the lesser of their maximum part and their number of parts is n.at n=27A325232
• G.f. A(x) satisfies: A(x) = 1 / ((1 + x) * (1 - x * A(3*x))).at n=5A348861
• Numbers k which have a factorization k = f1*f2*...*fr where the digits of {k, f1, f2, ..., fr} together give 0,1,...,9 exactly once.at n=21A370970
• Composite numbers with properties that its digits (which may appear with multiplicity) may not appear in any of its factors (wherein the digits may also appear with multiplicity) and the combined digits of the product and the factors must have at least one of each of the ten digits.at n=45A370972
• Numbers k which have a factorization k = f_1*f_2*...*f_r where f_i >= 1 and the digits of {k, f_1, f_2, ..., f_r} together give 0,1,...,9 exactly once.at n=37A372259