A204519 Square root of floor(A055851(n)/6).

0, 0, 0, 1, 2, 4, 11, 20, 40, 109, 198, 396, 1079, 1960, 3920, 10681, 19402, 38804, 105731, 192060, 384120, 1046629, 1901198, 3802396, 10360559, 18819920, 37639840, 102558961, 186298002

Offset: 1

Author

M. F. Hasler, Jan 15 2012

Keywords

• nonn
• base

Comments

Base-6 analog of A031150 [base 10], A204512 [base 8], A204517 (base 7), A204521 [base 5], A001353 [base 3], A001542 [base 2]. For bases 4 and 9, the corresponding sequence contains all integers.

Crossrefs

Cf. A055792, A055793, A055812, A204517, A204512, A204503 and A023110.

Programs

Mathematica

Sqrt[Floor[Select[Range[100000],IntegerQ[Sqrt[Quotient[#^2,6]]]&]^2/6]] (* Vaclav Kotesovec, Nov 26 2012 *)

PARI

b=6;for(n=1,2e9,issquare(n^2\b) & print1(sqrtint(n^2\b),","))

Formula

Conjecture (for n>=8): a(n) = 10*a(n-3) - a(n-6). - Vaclav Kotesovec, Nov 26 2012

Empirical g.f.: x^4*(x^3+4*x^2+2*x+1) / (x^6-10*x^3+1). - Colin Barker, Sep 15 2014

Extensions

More terms from Vaclav Kotesovec, Nov 26 2012