A256244 a(n) = sqrt(n + 2*A256243(n)).

3, 2, 3, 4, 3, 4, 3, 4, 5, 4, 5, 4, 5, 4, 5, 6, 5, 6, 5, 6, 5, 6, 5, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 10, 9, 10, 9, 10, 9, 10, 9, 10, 9, 10, 9, 10, 9, 10, 9, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 10, 11, 12

Offset: 1

Author

Zak Seidov, Mar 20 2015

Keywords

• nonn
• easy

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000196, A256243.

Programs

Mathematica

Table[m = 1; While[! IntegerQ[Sqrt[n + 2*m]], m++]; Sqrt[n + 2 m], {n, 100}] (* Michael De Vlieger, Mar 20 2015 *)

PARI

a(n)=m=1;while(!issquare(n+2*m),m++);sqrt(n+2*m)
vector(100,n,round(a(n))) \\ Derek Orr, Mar 22 2015

PARI

a(n)=my(s=sqrtint(n)); if((s-n)%2,s+1,s+2) \\ Charles R Greathouse IV, Mar 23 2015

Formula

sqrt(n) < a(n) <= sqrt(n) + 2. - Charles R Greathouse IV, Mar 23 2015