cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

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.

Original entry on oeis.org

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

Views

Author

Steven Finch, Jul 20 2015

Keywords

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.

Crossrefs

A195853 Decimal expansion of the lower limit of A139250(i)/i^2.

Original entry on oeis.org

4, 5, 1, 3, 0, 5, 8, 2, 8, 4, 5, 3, 1, 2, 2, 1, 3, 5, 8, 9, 6, 4, 0, 1, 3, 4, 2, 2, 8, 0, 4, 0, 0, 1, 2, 3, 5, 1, 0, 2, 0, 4, 1, 3, 8, 3, 2, 9
Offset: 0

Views

Author

Omar E. Pol, Sep 27 2011

Keywords

Comments

Constant mentioned in the Applegate-Pol-Sloane article, Section 5, the fractal-like structure. It is also mentioned in A139250 and A170927.
Note that at least there are 162 constants starting with 0.451305 in the Plouffe's Inverter.
Also evidently half the lower limit of A147562(n)/n^2; see A260239. - Steven Finch, Jul 21 2015

Examples

			0.451305...
		

References

  • D. Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191

Crossrefs

Extensions

a(6)-a(14) from Robert Price, Aug 18 2012
a(15)-a(47) from Robert Price, Aug 16 2015
Removed first fifteen terms as they were duplicated in the last edit by Robert Price, Dec 17 2018

A261313 Decimal expansion of the lower limit of A147562(i)/i^2.

Original entry on oeis.org

9, 0, 2, 6, 1, 1, 6, 5, 6, 9, 0, 6, 2, 4, 4, 2, 7, 1, 7, 9, 2, 8, 0, 2, 6, 8, 4, 5, 6, 0, 8, 0, 0, 2, 4, 7, 0, 2, 0, 4, 0, 8, 2, 7, 6, 6, 5, 9, 9, 1, 6, 6, 0, 7, 9, 5, 1, 8, 2, 5, 8, 6, 7, 3, 9, 6, 6, 6, 2, 1, 5, 2, 5, 0, 4, 4, 3, 3, 8, 5, 2, 7, 6, 6, 3, 8, 3
Offset: 0

Views

Author

Robert Price, Aug 14 2015

Keywords

Comments

Evidently twice the lower limit of A139250(n)/n^2 and thus twice A195853.

Examples

			0.90261165..
		

References

  • D. Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191

Crossrefs

Extensions

Name and first 10 terms suggested by Steven Finch, Jul 21 2015

A261895 Decimal expansion of the lower limit of A162795(i)/i^2.

Original entry on oeis.org

2, 2, 5, 6, 5, 2, 9, 1, 4, 2
Offset: 0

Views

Author

Robert Price, Sep 05 2015

Keywords

Comments

Sequence suggested by Omar E. Pol.
Similar to the constant mentioned in the Applegate-Pol-Sloane article, Section 5, the fractal-like structure. It is also mentioned in A139250 and A170927.
It appears that this sequence is a quarter of A261313 and half of A195853.

Examples

			0.2256529142...
		

References

  • D. Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191

Crossrefs

Programs

  • Mathematica
    T = 1; t[0] = 0; t[1] = 1; lst = {1};
    Do[twon = 2^n; Tmin = 1; imin = 1;
        Do[If[i == twon, t[i] = twon,
                         t[i] = 2*t[i - twon] + t[i - twon + 1];
                         If[OddQ[i], T = T + t[i];
                                     Ttest = T/(i*i)];
                                     If[ Ttest
    				

A261896 Consider the 2^n values of A162795(i)/i^2 for 2^n <= i < 2^(n+1); a(n) = value of i where this quantity is minimized.

Original entry on oeis.org

3, 5, 11, 25, 43, 89, 179, 361, 727, 1459, 2921, 5843, 11689, 23383, 46769, 93543, 187093, 374193, 748391, 1496785, 2993575, 5987157, 11974321, 23948647, 47897299, 95794607, 191589221, 383178449, 766356903, 1532713827, 3065427663, 6130855333, 12261710675, 24523421357, 49046842723
Offset: 0

Views

Author

Robert Price, Sep 05 2015

Keywords

Comments

Sequence suggested by Omar E. Pol.
Note that all values in this sequence are odd and that a(n) is approximately 2*a(n-1).

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.

Crossrefs

Programs

  • Mathematica
    T = 1; t[0] = 0; t[1] = 1; lst = {1};
    Do[twon = 2^n; Tmin = 1; imin = 1;
        Do[If[i==twon, t[i]=twon,
                       t[i]=2*t[i-twon]+t[i-twon+1];
                       If[OddQ[i], T=T+t[i];
                                   Ttest=T/(i*i)];
                                   If[Ttest
    				
Showing 1-5 of 5 results.