

A222819


a(n) = number of nontrivial reverse multipliers for base n.


5



0, 1, 1, 2, 2, 2, 4, 3, 2, 5, 4, 3, 6, 6, 3, 7, 5, 7, 7, 6, 5, 10, 10, 5, 7, 8, 5, 12, 11, 9, 12, 5, 8, 13, 9, 8, 12, 16, 8, 14, 11, 12, 16, 12, 10, 19, 15, 11, 11, 9, 10, 19, 18, 17, 18, 13, 9, 23, 14, 15, 21, 19, 14, 19, 12, 18, 16, 19, 17, 26, 17, 11, 20, 16, 15, 21, 13, 26, 24, 13
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

2,4


COMMENTS

If there is a number m such that the reversal of m in base n is c times m, then c is called a reverse multiplier for n. For example, 2 is a reverse multiplier for base n=5, since 8 (base 10) = 13 (base 5), and 2*8 = 16 (base 10) = 31 (base 5).
The trivial reverse multiplier 1 is excluded.


LINKS

N. J. A. Sloane, Table of n, a(n) for n = 2..100
N. J. A. Sloane, 2178 And All That, Fib. Quart., 52 (2014), 99120.
Anne Ludington Young, kReverse multiples, Fib. Q., 30 (1992), 126132.


CROSSREFS

Cf. A214927, A222817, A222818, A222820.
See A214927 for other crossreferences.
Sequence in context: A121806 A056944 A283681 * A194319 A208609 A249030
Adjacent sequences: A222816 A222817 A222818 * A222820 A222821 A222822


KEYWORD

nonn,base


AUTHOR

N. J. A. Sloane, Mar 13 2013


STATUS

approved



