A383912 Expansion of (1+x) * (1+2*x)/((1-x) * (1-2*x) * (1-3*x)).
1, 9, 45, 177, 621, 2049, 6525, 20337, 62541, 190689, 578205, 1746897, 5265261, 15844929, 47633085, 143095857, 429680781, 1289828769, 3871059165, 11616323217, 34855261101, 104578366209, 313760264445, 941331124977, 2824094038221, 8472483441249, 25417852976925
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (6,-11,6).
Programs
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PARI
a(n) = 10*3^n-3*2^(n+2)+3;
Formula
a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3).
a(n) = Sum_{k=0..3} |Stirling1(3,k)| * Stirling2(k+n,3).
a(n) = 10*3^n - 3*2^(n+2) + 3.