44660

Appears in sequences

• Numbers n such that the arithmetic, geometric and harmonic means of phi(n) and sigma(n) are all integers.at n=22A065146
• Diagonal in array of n-gonal numbers A081422.at n=34A081438
• Integers that are Rhonda numbers to base 9.at n=4A100973
• Sum of numbers under a triangle on a spiral staircase of width 10.at n=27A111080
• Numbers k such that sigma(k) = 9*phi(k).at n=11A163667
• Number of distinct solutions of sum{i=1..3}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 1..n-1.at n=18A180785
• Number of n X 5 0..1 arrays with every row and column running average nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=42A201501
• Principal diagonal of the convolution array A213819.at n=27A213820
• Alternating sum of 10-gonal (or decagonal) pyramidal numbers.at n=40A269441
• A(n,k) is the n-th Rhonda number to base A002808(k), the k-th composite number; square array A(n,k), n>=1, k>=1, read by antidiagonals.at n=32A291925
• Number of letters (0's and 1's) in the n-th iterate of the final-letter-removed mapping defined at A289035.at n=19A293077
• Integers n such that sigma(n)/phi(n) is a perfect square.at n=33A293391
• a(n) = Sum_{d|n} (-1)^(d-1) * (n/d)^n * binomial(d+n/d-2, d-1).at n=5A338689
• a(n) = Sum_{i+j+k+l=n, i,j,k,l >= 1} sigma(i)*sigma(j)*sigma(k)*sigma(l).at n=12A374977