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A161341
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First differences of A161340.
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2
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1, 26, 56, 260, 56, 392, 392, 2192, 56, 392, 392, 2744, 392, 2744, 2744, 16952, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 392, 2744, 2744, 19208, 2744, 19208, 19208, 125336, 56, 392, 392, 2744, 392, 2744, 2744, 19208, 392, 2744, 2744, 19208, 2744, 19208, 19208
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = A160429(n) for n>1 and n not a power of 2.
a(n) = A160429(n) - 3n*(3n - 1) for n>1 and n a power of 2.
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EXAMPLE
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Written as an irregular triangle in which row lengths give A011782 the sequence begins:
1;
26;
56, 260;
56, 392, 392, 2192;
56, 392, 392, 2744, 392, 2744, 2744, 16952;
56, 392, 392, 2744, 392, 2744, 2744, 19208, 392, 2744, 2744, 19208, 2744, ...
(End)
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PROG
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(PARI) f(n) = 8*7^hammingweight(n-1); \\ A160429
ispow2(n) = my(k); (n==2) || (ispower(n, , &k) && (k==2));
a(n) = if (n==1, 1, if (ispow2(n), f(n) - 3*n*(3*n - 1), f(n))); \\ Michel Marcus, Mar 15 2020
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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