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A061252
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a(n) = 16^n - 15^n.
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0
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0, 1, 31, 721, 14911, 289201, 5386591, 97576081, 1732076671, 30276117361, 522861237151, 8942430185041, 151728638820031, 2557404559011121, 42864668012537311, 715027614225987601, 11878335717996660991
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OFFSET
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0,3
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COMMENTS
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Number of ways to assign truth values to n quaternary conjunctions connected by disjunctions such that the proposition is true. For example, a(2) = 31, since for the proposition '(a & b & c & d) v (e & f & g & h)' there are 31 assignments that make the proposition true. - Ori Milstein, Dec 31 2022
Equivalently, the number of length-n words over the alphabet {0,1,..,15} with at least one letter = 15. - Joerg Arndt, Jan 01 2023
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LINKS
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FORMULA
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MATHEMATICA
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Table[16^n-15^n, {n, 0, 20}] (* or *) LinearRecurrence[{31, -240}, {0, 1}, 20] (* Harvey P. Dale, Jan 23 2021 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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