21462

Appears in sequences

• n satisfying sigma(n+1) = sigma(n-1).at n=28A055574
• Numbers k such that sigma(k-1) divides sigma(k+1).at n=34A067130
• Smallest of 4 consecutive numbers each divisible by a square.at n=34A070284
• Number of partitions into a square number of parts.at n=48A089333
• Numbers k such that the number of prime divisors of the k-th Catalan number (counted with multiplicity) divides k.at n=35A121612
• G.f.: A(x) = exp( Sum_{n>=1} 2^(n^2)/(1 - 2^n*x)^n * x^n/n ).at n=4A156910
• Integers that do not have a partition into a sum of an odd square and two (not necessarily distinct) triangular numbers.at n=39A191764
• Table of elementary symmetric functions a_k(1,2,5,6,...,n+2) (no 3,4).at n=48A196846
• Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).at n=29A223137
• Numbers k such that sigma(k+1) divides sigma(k-1).at n=29A227304
• a(n) = (4*n+3)*(4*n+2).at n=36A256833
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 694", based on the 5-celled von Neumann neighborhood.at n=33A273411
• Oblong numbers that are the sum of 2 successive primes.at n=30A298077
• Number of nX4 0..1 arrays with every element equal to 0, 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.at n=9A298550
• a(n) = n * Sum_{d|n} binomial(d+2,3)/d.at n=48A343544
• Prime gaps: differences between consecutive primes, starting at 10^100000.at n=31A365612