27504

Appears in sequences

• G.f.: x*(1-x^2)*(x^4+x^3-x^2+x+1) / (x^8-4*x^6-x^4-4*x^2+1).at n=16A005822
• Number of 2 X 2 non-singular integer matrices with entries from {0,...,n}.at n=12A062801
• Numbers that have exactly seven prime factors counted with multiplicity (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity).at n=14A109027
• Molecular topological indices of the path graphs P_n.at n=34A121318
• Number of permutations of floor(i*3/2), i=0..n-1, with all sums of 4 adjacent terms unique.at n=7A152333
• Numbers k such that phi(phi(k)) = sigma(rad(k)).at n=34A173748
• 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=11A195814
• Numbers n = p * q, where n, p, and q together contain all 10 digits at least once.at n=16A253172
• 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=11A253173
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 217", based on the 5-celled von Neumann neighborhood.at n=33A270911
• a(n) is the sum of the Wieferich and Wall-Sun-Sun residues of prime(n).at n=42A339639
• 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=28A370970
• 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=44A372259
• Numbers k such that sopfr(k + sopfr(k)) = sopfr(k) + sopfr(sopfr(k)), where sopfr = A001414.at n=29A376851
• Triangle read by rows: T(n,k) is the number of free polyominoes with n cells and length k, n >= 1, k = 1..n.at n=71A379624