Product_{n>=1} 1 / (1 - a(n)*x^n/n!) = 1 + arctan(x).

A353915

Product_{n>=1} 1 / (1 - a(n)*x^n/n!) = 1 + arctan(x).

Terms

    a(0) =1a(1) =-2a(2) =-2a(3) =-16a(4) =-16a(5) =16a(6) =-832a(7) =-22016a(8) =-27648a(9) =173568a(10) =-4228608a(11) =-57965568a(12) =-398991360a(13) =2554896384a(14) =-98606039040

External references