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A122439
Expansion of 1/(1-2x-x^2+4x^4).
1
1, 2, 5, 12, 25, 54, 113, 232, 477, 970, 1965, 3972, 8001, 16094, 32329, 64864, 130053, 260594, 521925, 1044988, 2091689, 4185990, 8375969, 16757976, 33525165, 67064346, 134149981, 268332404, 536714129, 1073503278, 2147120761
OFFSET
0,2
COMMENTS
Diagonal sums of number triangle A122438. Convolution of A052947 and 2^n.
MATHEMATICA
CoefficientList[Series[1/(1 - 2x - x^2 + 4x^4), {x, 0, 31}], x] (* Robert G. Wilson v, Sep 14 2006 *)
LinearRecurrence[{2, 1, 0, -4}, {1, 2, 5, 12}, 40] (* Harvey P. Dale, Jul 30 2024 *)
CROSSREFS
Sequence in context: A116734 A101836 A262667 * A063807 A182202 A116715
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Sep 05 2006
EXTENSIONS
More terms from Robert G. Wilson v, Sep 14 2006
STATUS
approved