A260239 Consider the 2^n values of A147562(i)/i^2 for 2^n <= i < 2^(n+1); a(n) = value of i where this quantity is minimized.

1, 3, 5, 11, 23, 45, 91, 183, 365, 731, 1461, 2923, 5847, 11693, 23387, 46775, 93549, 187099, 374197, 748395, 1496791, 2993581, 5987163, 11974327, 23948653, 47897307, 95794615, 191589229, 383178459, 766356917, 1532713835, 3065427671

Offset: 0

Author

Steven Finch, Jul 20 2015

Keywords

• nonn

Comments

This sequence (for Ulam-Warburton) is analogous to A170927 (for toothpicks). Further, the lower limit of A147562(n)/n^2 evidently approaches twice the constant given in A195853.

Note that all values in this sequence are odd and that a(n)=2*a(n-1)+1 or a(n)=2*a(n-1)-1. - Robert Price, Aug 14 2015

References

• D. Applegate, O. E. Pol and N. J. A. Sloane, The toothpick sequence and other sequences from cellular automata, Congressus Numerantium, v. 206 (2010) 157-191.

Links

• Robert Price, Table of n, a(n) for n = 0..291
• D. Applegate, O. E. Pol and N. J. A. Sloane, The toothpick sequence and other sequences from cellular automata; also available at arXiv:1004.3036v2, [math.CO], 2010.
• Steven R. Finch, Toothpicks and Live Cells, July 21, 2015. [Cached copy, with permission of the author]

Crossrefs

Cf. A139250, A147562, A170927, A195853.