A122440
Riordan array ((3-sqrt(1+8x))/2, (sqrt(1+8x)-1)/4).
Original entry on oeis.org
1, -2, 1, 4, -4, 1, -16, 16, -6, 1, 80, -80, 32, -8, 1, -448, 448, -184, 52, -10, 1, 2688, -2688, 1120, -336, 76, -12, 1, -16896, 16896, -7104, 2208, -544, 104, -14, 1, 109824
Offset: 0
Triangle begins
1,
-2, 1,
4, -4, 1,
-16, 16, -6, 1,
80, -80, 32, -8, 1,
-448, 448, -184, 52, -10, 1,
2688, -2688, 1120, -336, 76, -12, 1
A122439
Expansion of 1/(1-2x-x^2+4x^4).
Original entry on oeis.org
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
-
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 *)
Showing 1-2 of 2 results.
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