

A061916


Obtain m by omitting trailing zeros from n; a(n) = smallest k such that k*m is a palindrome with even digits, or 1 if no such multiple exists.


3



1, 2, 1, 2, 1, 1, 1, 98, 1, 74, 2, 2, 37, 154, 49, 1, 29, 38, 37, 34, 1, 286, 1, 36, 37, 1, 77, 329144, 31, 16, 2, 28, 132, 2, 19, 1, 23, 6, 17, 154, 1, 542, 143, 1602, 1, 1, 18, 6, 88, 14, 1, 824, 77, 8, 164572, 1, 143, 1198, 8, 1154, 1, 1126, 14, 962, 66, 1, 1, 998, 121, 12, 98, 65984, 592, 274, 3, 1, 529, 26, 77, 358
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OFFSET

0,2


COMMENTS

a(n) = 1 if and only if m ends with the digit 5.


LINKS

Table of n, a(n) for n=0..79.
P. De Geest, Smallest multipliers to make a number palindromic.


EXAMPLE

For n = 30 we have m = 3; 3*2 = 6 is a palindrome with even digits, so a(30) = 2.


PROG

(ARIBAS): stop := 500000; for n := 0 to 80 do k := 1; test := true; while test and k < stop do mp := omit_trailzeros(n)*k; if test := not all_even(mp) or mp <> int_reverse(mp) then inc(k); end; end; if k < stop then write(k, " "); else write(1, " "); end; end;


CROSSREFS

Cf. A050782, A062293, A061816, A061906. Values of k*m are given in A061915.
Sequence in context: A264969 A320301 A324510 * A076348 A263835 A113310
Adjacent sequences: A061913 A061914 A061915 * A061917 A061918 A061919


KEYWORD

base,easy,sign


AUTHOR

Klaus Brockhaus, Jun 25 2001


STATUS

approved



