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”).

A027923
a(n) = least k such that E{1,2,...,k} >= 1^2 + 2^2 + ... + n^2, where E = 2nd elementary symmetric function.
0
1, 2, 3, 3, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 16, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 24, 24, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 28, 29
OFFSET
1,2
FORMULA
min{k: A000914(k) >= A000330(n)}. - R. J. Mathar, Oct 31 2011
CROSSREFS
Sequence in context: A119466 A100922 A047785 * A167743 A020888 A196393
KEYWORD
nonn
STATUS
approved