login
A222817
Irregular triangle read by rows: row n gives list of nontrivial reverse multipliers for base n.
6
2, 3, 2, 4, 2, 5, 3, 6, 2, 3, 5, 7, 2, 4, 8, 4, 9, 2, 3, 5, 7, 10, 2, 3, 5, 11, 5, 6, 12, 2, 3, 4, 6, 9, 13, 2, 3, 4, 7, 11, 14, 3, 7, 15, 2, 4, 5, 8, 10, 11, 16, 2, 5, 7, 8, 17, 3, 4, 6, 7, 9, 14, 18, 2, 3, 4, 6, 9, 13, 19
OFFSET
3,1
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.
The last entry in each row is n-1; the number of terms in row n is A222819(n).
LINKS
N. J. A. Sloane, 2178 And All That, arXiv:1307.0453 [math.NT], 2013; Fib. Quart., 52 (2014), 99-120.
Anne Ludington Young, k-Reverse multiples, Fib. Q., 30 (1992), 126-132.
EXAMPLE
Triangle begins:
2,
3,
2,4,
2,5,
3,6,
2,3,5,7,
2,4,8,
4,9,
2,3,5,7,10,
2,3,5,11,
5,6,12,
2,3,4,6,9,13,
2,3,4,7,11,14,
3,7,15,
...
CROSSREFS
See A214927 for other cross-references.
Sequence in context: A331252 A162908 A373558 * A344324 A309428 A328368
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Mar 13 2013
STATUS
approved