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%I #14 Jul 12 2018 08:49:49
%S 0,2,2,6,4,20,6,42,8,864,20,42086,420,208,42,420,64,8642086,864,
%T 642086,20,42,42086,6420864,864,-1,208,864,420,8642,420,
%U 86420864208642,64,420864208642086,8642086,420,864,86420864208642,642086,86420864208642086420864208642,-1,642086420864208642,42,86,2086420864,6420864208642086420,6420864,2086420864208642086,864,208642,-1,864208642086420864208642086420864
%N Smallest multiple of n with property that digits are even and each digit is two less (mod 10) than the previous digit, if such a multiple exists; otherwise -1.
%H Don Reble, <a href="/A062885/a062885.txt">Analysis of this sequence</a>
%H <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a>
%e a(7) = 42 = 7*6 has decreasing even digits.
%e For n = 25, the conditions require that the desired multiple 25k have k even, i.e., 25k = 25(2i) = 50i = (5i)(10). Thus the final digit is 0, so the next-to-last digit must be 2, but this is impossible since 5i always ends in 0 or 5. Thus a(25) = -1. - _John W. Layman_, Nov 01 2001
%Y Cf. A062884.
%K base,easy,nice,sign
%O 0,2
%A _Amarnath Murthy_, Jun 28 2001
%E More terms and better description from _John W. Layman_, Nov 01 2001
%E Further terms from _Jud McCranie_, Nov 01 2001