20457

Appears in sequences

• Sum of 12 nonzero 8th powers.at n=39A003390
• Numerators of continued fraction convergents to sqrt(754).at n=8A042452
• Number of triangulations of the cyclic polytope C(n, n-4).at n=21A066342
• a(n) = (3*n+4)*2^(n-3)-(2*n-1).at n=10A066374
• Number of n-digit lunar primes.at n=4A087636
• E.g.f.: exp(-1)*Sum((1+2*x)^binomial(n,2)/n!, n=0..infinity).at n=5A094089
• 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=6A195814
• Numbers n = p * q, where n, p, and q together contain all 10 digits at least once.at n=6A253172
• 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=6A253173
• Total number of polydivisible numbers in base n.at n=8A271374
• Numerator of best rational approximation x/y of sqrt(k), y<=k, with k given by A306972. The corresponding denominators are given in A306974.at n=31A306973
• 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=19A370970
• 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=42A370972
• 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=35A372259