A085141 Greatest nonnegative integer k such that k(3k+1)/2 <= n.

0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8

Offset

0,8

Links

Table of n, a(n) for n=0..104.

Formula

a(n) = floor((sqrt(24n+1)-1)/6).

a(A005449(n)) = n.

Prog

(PARI) a(n)=if(n<0, 0, (sqrtint(24*n+1)-1)\6)

Crossrefs

Cf. A005449.

Sequence in context: A071842 A344517 A371355 * A082896 A079416 A135664

Adjacent sequences: A085138 A085139 A085140 * A085142 A085143 A085144

Keyword

nonn,easy

Author

Michael Somos, Jun 19 2003

Status

approved