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A036220 Expansion of 1/(1-3*x)^7; 7-fold convolution of A000244 (powers of 3). 5
1, 21, 252, 2268, 17010, 112266, 673596, 3752892, 19702683, 98513415, 472864392, 2192371272, 9865670724, 43257171636, 185387878440, 778629089448, 3211844993973, 13036312034361, 52145248137444, 205836505805700 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) = A027465(n+7,7) (O. Gerard's triangle).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..400

FORMULA

a(n) = 3^n*binomial(n+6, 6).

G.f.: 1/(1-3*x)^7.

MAPLE

seq(binomial(n+6, 6)*3^n, n=0..19); # Zerinvary Lajos, Jun 16 2008

PROG

(Sage) lucas_number2(n, 3, 0)*binomial(n, 6)/729 for n in range(6, 26)] # Zerinvary Lajos, Mar 10 2009

(MAGMA) [3^n*Binomial(n+6, 6): n in [0..30]]; // Vincenzo Librandi, Oct 15 2011

CROSSREFS

Cf. A000244, A027465.

Sequence in context: A165108 A282923 A023019 * A022649 A165094 A322500

Adjacent sequences:  A036217 A036218 A036219 * A036221 A036222 A036223

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

STATUS

approved

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Last modified July 12 13:27 EDT 2020. Contains 335663 sequences. (Running on oeis4.)