A099357 From P-positions in a certain game. Pile 2 tokens for select function x1*[1+(-)^x1]+1.

0, 2, 5, 7, 18, 33, 51, 53, 75, 77, 103, 105, 135, 137, 171, 174, 176, 218, 220, 266, 268, 318, 320, 374, 376, 434, 436, 498, 500, 567, 637, 639, 713, 715, 793, 795, 877, 879, 965, 967, 1057, 1059, 1153, 1155, 1253, 1255, 1358, 1465, 1575, 1577

Offset

0,2

Comments

Table 10 in Fraenkel is incorrect from n=6 onward. - Nathaniel Johnston, Apr 28 2011

Links

Nathaniel Johnston, Table of n, a(n) for n = 0..10000

A. S. Fraenkel, New games related to old and new sequences, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 4, Paper G6, 2004.

Formula

See A099356.

Maple

a:=proc(n) option remember: local j, t: if(n=0)then return 0: else t:=a(n-1)+1: for j from 0 to n-1 do if(t=b(j))then return t+1: elif(t<b(j))then break: fi: od: return t: fi: end:
b:=proc(n) option remember: if(n=0)then return 0: else return b(n-1) + (-1)^a(n-1)*a(n-1) + a(n) + 1: fi: end:
seq(b(n), n=0..70); # Nathaniel Johnston, Apr 28 2011

Crossrefs

Cf. A099352 - A099356.

Sequence in context: A392052 A168035 A247323 * A306918 A027038 A341322

Adjacent sequences: A099354 A099355 A099356 * A099358 A099359 A099360

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 16 2004

Extensions

Edited and corrected by Nathaniel Johnston, Apr 28 2011

Status

approved