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A309407 a(n) = round(sqrt(3*n + 9/4)), with a(0) = 1. 2
1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Diverges from A046693 at positions in A308766.

For the first 1750 terms, A046693(n)-a(n) is either 0 or 1.

LINKS

Table of n, a(n) for n=0..88.

Ed Pegg Jr, Sparse Rulers.

FORMULA

a(n) = round(sqrt(3*n + 9/4)).

MATHEMATICA

Table[If[n == 0, 1, Round[Sqrt[3 n + 9/4]]], {n, 0, 88}]

CROSSREFS

Cf. A046693, A308766, A326499.

Sequence in context: A003057 A239308 A216256 * A046693 A196376 A156077

Adjacent sequences:  A309404 A309405 A309406 * A309408 A309409 A309410

KEYWORD

nonn,easy

AUTHOR

Ed Pegg Jr, Jul 29 2019

STATUS

approved

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Last modified December 5 22:37 EST 2019. Contains 329782 sequences. (Running on oeis4.)