A211807 - OEIS

A211807

Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^3<=x^3+y^3.

1, 5, 16, 38, 73, 123, 194, 290, 415, 569, 754, 978, 1245, 1559, 1914, 2320, 2781, 3303, 3888, 4532, 5243, 6027, 6890, 7836, 8853, 9957, 11152, 12440, 13827, 15301, 16878, 18564, 20363, 22273, 24290, 26430, 28697, 31093, 33612, 36262

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Row 3 of A211808; see A211790 for a discussion and guide to related sequences.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

f:= proc(n) local x;

n + add(2*floor(((x^3+n^3)/2)^(1/3)), x=1..n-1)

end proc:

ListTools:-PartialSums(map(f, [$1..50])); # Robert Israel, Jan 26 2025

MATHEMATICA

(See the program at A211808.)

CROSSREFS

Cf. A211790, A211808.

Sequence in context: A041044 A042645 A218259 * A174723 A011932 A357289

Adjacent sequences: A211804 A211805 A211806 * A211808 A211809 A211810

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 22 2012

STATUS

approved