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A052150
Partial sums of A000340, second partial sums of A003462.
7
1, 6, 24, 82, 261, 804, 2440, 7356, 22113, 66394, 199248, 597822, 1793557, 5380776, 16142448, 48427480, 145282593, 435847950, 1307544040, 3922632330, 11767897221, 35303691916, 105911076024, 317733228372, 953199685441
OFFSET
0,2
COMMENTS
Convolution of the powers of 3 with the triangular numbers [1, 3, 6, 10, ...]. - Enrique Navarrete, Nov 04 2025
REFERENCES
A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 189, 194-196.
Paulo Ribenboim, The Little Book of Big Primes, Springer-Verlag, N.Y., 1991, p. 53.
FORMULA
a(n) = (3^(n+3) - (2*n^2 + 12*n + 19))/8.
a(n) = 3*a(n-1)+C(n+2,2); a(0)=1.
a(n) = Sum_{k=0..n} binomial(n+3, k+3)*2^k. - Paul Barry, Aug 20 2004
From Colin Barker, Dec 18 2012: (Start)
a(n) = 6*a(n-1) - 12*a(n-2) + 10*a(n-3) - 3*a(n-4).
G.f.: 1/((x-1)^3*(3*x-1)). (End)
E.g.f.: exp(x)*(27*exp(2*x) - 2*x^2 - 14*x - 19)/8. - Enrique Navarrete, Nov 04 2025
MATHEMATICA
LinearRecurrence[{6, -12, 10, -3}, {1, 6, 24, 82}, 40] (* Harvey P. Dale, Sep 05 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Barry E. Williams, Jan 23 2000
STATUS
approved