1610563584domain: NAppears in sequencesRelates row sums of Pascal's triangle to expansion of cos(x)/exp(x).at n=30A100216a(n) = 3*2^(n-1)*(2^n-1).at n=14A103897a(n) = 2*a(n-1) + 2*a(n-2) - 4*a(n-3) with n>2, a(0)=0, a(1)=1, a(2)=3.at n=30A135094Numbers k such that denominator(sigma(k)/k) = 6.at n=3A262359