18414

Appears in sequences

• Sum of orders of all 2 X 2 matrices with entries mod n.at n=7A006045
• a(n) = n*(19*n + 1)/2.at n=44A022277
• Numbers k such that sigma(k+1) divides sigma(k), where sigma(k) is the sum of positive divisors of k.at n=24A058073
• Numbers k such that gcd(sigma(k), sigma(k+1)) > k.at n=35A066025
• Number of totally ramified extensions over Q_2 with degree n in the algebraic closure of Q_2.at n=17A100979
• Least K such that K*p(n)#-1 is the first of twin primes and 2*(K*p(n)#-1)+1 is prime, so K*p(n)#-1 is the first of twin primes and a Sophie Germain prime.at n=46A117848
• Numbers k such that sigma(k) = 2*sigma(k+1).at n=12A163193
• Multiples of 682.at n=27A200860
• Number of nX3 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 0 and 0 1 1 vertically.at n=9A207903
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 929", based on the 5-celled von Neumann neighborhood.at n=23A273781
• Record high values in A245340.at n=9A370956