A078737 Denominators of convergents to sqrt(e).
1, 1, 2, 3, 17, 20, 37, 353, 390, 743, 10049, 10792, 20841, 365089, 385930, 751019, 16157329, 16908348, 33065677, 843550273, 876615950, 1720166223, 50761436417, 52481602640, 103243039057, 3459501891521, 3562744930578, 7022246822099
Offset: 1
Programs
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PARI
a(n)=component(component(contfracpnqn(contfrac(exp(1/2),n)),1),2)
Formula
Let y(n, x)=sum(k=0, n, (n+k)!*(x/2)^k/((n-k)!*k!)) then : a(3*n-1)=(1/2)*(|y(n, -4)|- |y(n-1, -4)|); a(3*n)=(1/2)*(|y(n, -4)|+ |y(n-1, -4)|); a(3*n+1)=|y(n, -4)|