130801

Appears in sequences

• Positive integers k such that k divides 12^k - 1.at n=11A014951
• Numbers k such that k | 10^k + 1.at n=14A015958
• Numbers k that divide 6^k + 5^k.at n=17A045595
• Expansion of 1/((1-2*x)*(1+x+2*x^2)).at n=18A089977
• Odd decagonal pyramidal numbers.at n=23A218330
• Numbers n dividing u(n), where the Lucas sequence is defined u(i) = u(i-1) - 3*u(i-2) with initial conditions u(0)=0, u(1)=1.at n=12A228440
• Number of compositions of n such that the first part is 1 and the second differences of the parts are in {-n,...,n}.at n=19A239561
• Numbers k such that sigma_2(k) = sigma_2(phi(k)).at n=3A333338
• a(n) is the n-th number m that divides n^m - 1 (or 0 if m does not exist).at n=11A333433