Coefficient of x^n in the expansion of (1+x+x^3)^(3*n).

A372374

Coefficient of x^n in the expansion of (1+x+x^3)^(3*n).

Terms

    a(0) =1a(1) =3a(2) =15a(3) =93a(4) =627a(5) =4368a(6) =30957a(7) =222015a(8) =1606803a(9) =11713260a(10) =85884660a(11) =632726988a(12) =4679850525a(13) =34729198260a(14) =258460942671

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