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A274768
Lexicographically earliest increasing sequence a, b, c, ... such that every partial product (1-x^a), (1-x^a)(1-x^b), (1-x^a)(1-x^b)(1-x^c), ... has coefficients -1, 0, 1 only.
0
1, 2, 3, 5, 7, 8, 9, 17, 26, 43, 46, 60, 175, 221, 396, 617, 1013, 1630, 2643, 4273, 6916, 11189, 18105, 29294, 47399, 76693, 124092, 200785, 324877, 525662, 850539, 1376201, 2226740, 3602941, 5829681, 9432622, 15262303, 24694925, 39957228, 64652153, 104609381
OFFSET
1,2
FORMULA
Empirical g.f.: x*(1 + x - x^4 - 4*x^5 - 6*x^6 - 23*x^10 - 29*x^11 + 69*x^12 - 14*x^13) / (1 - x - x^2). - Colin Barker, Nov 13 2016
EXAMPLE
a(4) = 5 because (1-x), (1-x)(1-x^2), and (1-x)(1-x^2)(1-x^3)(1-x^5) all have coefficients -1, 0, 1, but (1-x)(1-x^2)(1-x^3)(1-x^4) doesn't.
CROSSREFS
Sequence in context: A029601 A290985 A182758 * A272667 A076385 A152604
KEYWORD
nonn
AUTHOR
Jeffrey Shallit, Jul 05 2016
EXTENSIONS
a(19)-a(41) from Jon E. Schoenfield, Nov 12 2016
STATUS
approved