27688

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 83.at n=38A031581
• Triangle read by rows: T(n,k) is the number of k-matchings in the P_3 X P_n lattice graph.at n=45A100245
• Real part of (n + i)^5.at n=8A121672
• Positive numbers of the form x^5-10x^3*y^2+5x*y^4 (where x,y are integers and x>y).at n=7A135791
• Numbers of the form x^5-10x^3*y^2+5x*y^4 (where x,y are integers).at n=26A135793
• 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=49A185718
• The least integer k >= 0 for which A328578(k) = A257993(A276086(A276086(k))) = n.at n=23A328761