128180

Appears in sequences

• Square roots of sums of squares of divisors in A046655.at n=22A046656
• Numbers m such that DivisorSigma(4*k-2, m) mod m = 0 holds presumably for all k; that is, (4k-2)-power-sums of divisors of m are divisible by m for all k.at n=21A066290
• Smallest k such that k and k+n have the same prime signature that is different from all previous terms.at n=24A085876
• Numbers k that are the hypotenuse of exactly 40 distinct integer-sided right triangles, i.e., k^2 can be written as a sum of two squares in 40 ways.at n=25A097282
• Ratio of quadruple Sum of k^2-1 to quadruple sum of k made into an integer sequence: (1/6)*(-1 + n)*(2 + n)*(3 + n)*(7 + n).at n=26A130863
• For every positive integer m, let u(m) = (d(1),d(2),...,d(k)) be the unitary divisors of m. The sequence (a(n)) consists of successive numbers m which d(k)/d(1) + d(k-1)/d(2) + ... + d(k)/d(1) is an integer.at n=23A229996
• Numbers such that A017666(n) = A017668(n).at n=7A261989
• Numbers whose ternary and Zeckendorf representations are both palindromic.at n=10A329459
• Dirichlet convolution of A011782 (2^(n-1)) with A349451 (Dirichlet inverse of Fibonacci numbers).at n=17A349566
• Numbers k such that the sum of the squares of the odd divisors of k (A050999) is divisible by k.at n=30A355543