OFFSET
1,2
COMMENTS
The next term is too large to include.
a(n) = number of compositions of a(1) + number of compositions of a(2) + ... + number of compositions of a(n-1) for n > 2.
FORMULA
a(n) = n for n <= 2; thereafter a(n) = Sum_{k=1..n-1} 2^(a(k)-1).
EXAMPLE
a(5) = 71, 71 in base 2 (reverse order of digits) = 1110001.
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123 7
MATHEMATICA
a[n_] := a[n] = If[n <= 3, n, 2^(a[n - 1] - 1) + a[n - 1]]; Table[a[n], {n, 1, 6}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 08 2020
STATUS
approved