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A222818 Irregular triangle read by rows: row n gives list of reverse multipliers for base n. 3
1, 1, 2, 1, 3, 1, 2, 4, 1, 2, 5, 1, 3, 6, 1, 2, 3, 5, 7, 1, 2, 4, 8, 1, 4, 9, 1, 2, 3, 5, 7, 10, 1, 2, 3, 5, 11, 1, 5, 6, 12, 1, 2, 3, 4, 6, 9, 13, 1, 2, 3, 4, 7, 11, 14, 1, 3, 7, 15, 1, 2, 4, 5, 8, 10, 11, 16, 1, 2, 5, 7, 8, 17, 1, 3, 4, 6, 7, 9, 14, 18, 1, 2, 3, 4, 6, 9, 13, 19 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

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 included.

The last entry in each row is n-1; the number of terms in row n is A222820(n).

REFERENCES

For a complete list of references and links related to this problem see A214927.

LINKS

Table of n, a(n) for n=2..90.

N. J. A. Sloane, Table giving n, number of nontrivial reverse multipliers, list of nontrivial reverse multipliers, for n = 3..50

N. J. A. Sloane, 2178 And All That, Fib. Quart., 52 (2014), 99-120.

Anne Ludington Young, k-Reverse multiples, Fib. Q., 30 (1992), 126-132.

EXAMPLE

Triangle begins:

1,

1,2,

1,3,

1,2,4,

1,2,5,

1,3,6,

1,2,3,5,7,

1,2,4,8,

1,4,9,

1,2,3,5,7,10,

1,2,3,5,11,

1,5,6,12,

1,2,3,4,6,9,13,

1,2,3,4,7,11,14,

1,3,7,15

...

CROSSREFS

Cf. A214927, A222817, A222819, A222820.

See A214927 for other cross-references.

Sequence in context: A304038 A301983 A165416 * A057059 A169896 A210208

Adjacent sequences:  A222815 A222816 A222817 * A222819 A222820 A222821

KEYWORD

nonn,tabf

AUTHOR

N. J. A. Sloane, Mar 13 2013

STATUS

approved

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Last modified February 18 19:50 EST 2019. Contains 320262 sequences. (Running on oeis4.)