login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A219227
a(n) is the sum of n addends nested as follows: floor(f(floor(f(...(n)...)))) where f(x) = x^(1/3).
1
1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 67, 68, 69, 70, 71, 72, 73
OFFSET
1,2
COMMENTS
Its complement is 8, 28, 66, 128, 220, 348, 518, 519, 737, 1009, 1341, 1739, 2209, 2757, 3389, 4111, 4929, ..., .
EXAMPLE
For n=8, floor(8^(1/3))=2, and floor(floor(8^(1/3))^(1/3))=1 as do the remaining six terms, so a(8) = 2 + 7*1 = 9.
MATHEMATICA
a[n_] := Plus @@ Rest@ NestList[ Floor[#^(1/3)] &, n, n]; Array[a, 60]
CROSSREFS
Cf. A181092.
Sequence in context: A004727 A102352 A248182 * A007412 A270420 A336592
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Nov 15 2012
STATUS
approved