

A113917


Maximal element of Image^inf({ 2 }) under repeated basen zerosplit squaring.


2




OFFSET

2,1


COMMENTS

Define f_b(x) to be the set of base b numbers left after splitting x^2 at its zero digits and Image_b(S) = union_{x in S}{ { x } union f_b(S) }, then a(n) = max(Image_n^inf({ 2 }))
Conjecture: a(n) is finite for all n


LINKS

Table of n, a(n) for n=2..8.
Hugo van der Sanden, Perl and C implementations, Feb 03 2015


EXAMPLE

f_10(29648) = { 4, 39, 879 } since 29648^2 = 879003904;
a(8) = 4 since Image_8({ 2 }) = { 2, 4 } and f_8({ 2, 4 }) = { 2, 4 } and max({ 2, 4 }) is 4.


CROSSREFS

Cf. A113918.
Sequence in context: A263076 A162554 A167840 * A259487 A329663 A069793
Adjacent sequences: A113914 A113915 A113916 * A113918 A113919 A113920


KEYWORD

nonn,hard


AUTHOR

Hugo van der Sanden extending a suggestion from David W. Wilson, Jan 31 2006


EXTENSIONS

Corrected by Hugo van der Sanden, Feb 03 2015


STATUS

approved



