20344

Appears in sequences

• Expansion of 1/(1-x^3-x^4-x^5-x^6-x^7).at n=33A017820
• Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite MFI = ZSM-5 Nan[AlnSi96-nO192] starting with a T10 atom.at n=13A019169
• [ (4th elementary symmetric function of S(n))/(first elementary symmetric function of S(n)) ], where S(n) = {first n+3 positive integers congruent to 1 mod 4}.at n=4A024387
• Interprimes which are of the form s*prime, s=8.at n=30A075283
• Convolution of 5^n and floor(n/2).at n=8A097139
• Numbers n such that z(n) and z(n+1) are both prime, where z(n) = a^d + b^d + c^d + ..., where a*b*c* ... is the prime factorization of n and d is the largest digit of n.at n=17A109280
• For positive n with prime decomposition n = Product_{j=1..m} (p_j^k_j) define A_n = Sum_{j=1..m} (p_j*k_j) and B_n = Sum_{j=1..m} (p_j^k_j). This sequence gives those n for which A_n and B_n are both prime and B_n = A_n + 2 (i.e., form a twin prime pair).at n=37A185718
• Numbers n such that gcd(n, phi(n)) = gcd(phi(n), sigma(n)) = gcd(sigma(n), n) = tau(n).at n=36A217301
• Number of polyominoes of n cells with both diagonal symmetries, for which the 180-degree rotational symmetry has an axis that coincides with the center of a square, but without 90-degree rotational symmetry.at n=39A351159
• Numbers that are a sum of both four and six consecutive prime numbers.at n=35A380433