1,1

Conjectures. 1) For every n, a(n)>0; 2) for n>=3, a(n)==0 (mod 10).

If 1) is true, then A215113 is unbounded.

The corresponding positions m=m(n) such that A214723(m)=a(n) are 1,3,12,132,2074,18625,2138668. m(8) exists and the calculations show that it is >= 24866450, although up to now the exact its value is unknown.

Table of n, a(n) for n=1..9.

Cf. A214723, A215113.

Sequence in context: A173734 A219524 A259852 * A171371 A092692 A001151

Adjacent sequences: A215171 A215172 A215173 * A215175 A215176 A215177

nonn,more

Vladimir Shevelev, Zak Seidov, Robert G. Wilson v, Aug 05 2012

a(9) from Donovan Johnson, Aug 19 2012

approved