A173510 a(n) = a(n-1) + a(n-2) - floor( a(n-1)/2 ).

2, 1, 3, 3, 5, 6, 8, 10, 13, 17, 22, 28, 36, 46, 59, 76, 97, 125, 160, 205, 263, 337, 432, 553, 709, 908, 1163, 1490, 1908, 2444, 3130, 4009, 5135, 6577, 8424, 10789, 13819, 17699, 22669, 29034, 37186, 47627, 61000, 78127, 100064, 128159, 164144, 210231, 269260, 344861, 441691

Offset

0,1

Comments

The limiting ratio a(n+1)/a(n)is:1.2807764064

Links

Table of n, a(n) for n=0..50.

Mathematica

l[0] = 2; l[1] = 1;
l[n_] := l[n] = l[n - 1] + l[n - 2] - Floor[l[n - 1]/2]
Table[l[n], {n, 0, 30}]
RecurrenceTable[{a[0]==2, a[1]==1, a[n]==a[n-1]+a[n-2]-Floor[a[n-1]/2]}, a, {n, 50}] (* Harvey P. Dale, Sep 03 2013 *)

Prog

(Maxima) A173510[n] := block(
        if equal(n, 0) then return(2) ,
        if equal(n, 1) then return(1)
        else
        return(ev(A173510[n-1]+A173510[n-2]-floor(A173510[n-1]/2)))
)$ /* R. J. Mathar, Mar 11 2012 */

Crossrefs

Cf. A000032.

Sequence in context: A357643 A034394 A058689 * A238785 A241389 A190568

Adjacent sequences: A173507 A173508 A173509 * A173511 A173512 A173513

Keyword

nonn

Author

Roger L. Bagula, Nov 23 2010

Status

approved