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A367591
Expansion of 1/((1-x) * (1-3*x)^3).
2
1, 10, 64, 334, 1549, 6652, 27064, 105796, 401041, 1483606, 5380840, 19198306, 67559437, 234963352, 808919632, 2760370984, 9346519297, 31429487170, 105039380080, 349114288150, 1154561484781, 3801030845140, 12462203297224, 40705156945324, 132494756301649
OFFSET
0,2
FORMULA
a(n) = ((2*n^2+4*n+3) * 3^(n+1) - 1)/8.
PROG
(PARI) a(n) = ((2*n^2+4*n+3)*3^(n+1)-1)/8;
CROSSREFS
Partial sums of A027472.
Sequence in context: A245068 A055855 A061183 * A241401 A219934 A155618
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Nov 24 2023
STATUS
approved