A336827 a(n) is the largest integer that can be written in two bases smaller than n as mutually-reversed strings of digit(s), for n>=4.

1, 22, 22, 9831, 314767045, 1916060910, 455075911977

Offset

4,2

Links

Table of n, a(n) for n=4..10.

Example

a(5) is 22 because 22 = 211 (base 3) = 112 (base 4) is the largest such integer with both bases < 5 (here 3 and 4).
a(6) is also 22 because there are no larger such integers with both bases < 6.
a(7) is 9831 because 9831 = 303311 (base 5) and 113303 (base 6) is the largest such integer with both bases < 7 (here 5 and 6).

Crossrefs

Cf. A336733, A336768.

Sequence in context: A165843 A223821 A048429 * A004463 A152835 A004511

Adjacent sequences: A336824 A336825 A336826 * A336828 A336829 A336830

Keyword

nonn,base,more

Author

Michel Marcus, Aug 05 2020

Extensions

a(9)-a(10) from Bert Dobbelaere, Sep 20 2020

Status

approved