A222816 - OEIS

%I #23 Aug 20 2021 04:23:03

%S 8,48,144,208,248,744,1008,1248,3744,5008,5208,6048,6248,18744,25008,

%T 26208,30048,31248,90144,93744,125008,126008,130208,131208,150048,

%U 151048,155248,156248,450144,468744,625008,631008,650208,656208,750048,756048,775248,781248

%N Numbers k that divide the base-5 reversal of k.

%C The base-B reversal of k is obtained by writing k in base B and reversing the order of the digits.

%H N. J. A. Sloane, <a href="/A222816/b222816.txt">Table of n, a(n) for n = 1..57</a>

%H Leonard F. Klosinski and Dennis C. Smolarski, <a href="http://www.jstor.org/stable/2688542">On the Reversing of Digits</a>, Math. Mag., 42 (1969), 208-210. [Gives a(1)]

%H N. J. A. Sloane, <a href="http://arxiv.org/abs/1307.0453">2178 And All That</a>, arXiv:1307.0453 [math.NT], 2013; Fib. Quart., 52 (2014), 99-120.

%e 8 in base 5 is 13_5; its reverse is 31_5, which is 16 in base 10, and 8 divides 16, so 8 is in the sequence.

%t Select[Range[10^6],Divisible[s=FromDigits[Reverse@IntegerDigits[#,5],5],#]&&s!=#&] (* _Giorgos Kalogeropoulos_, Aug 20 2021 *)

%o (PARI) isok(n) = (rdn = subst(Polrev(digits(n,  5)), x, 5)) && (rdn != n) && (rdn % n) == 0; \\ _Michel Marcus_, Oct 10 2014

%Y Cf. A214927, A091079.

%K nonn,base

%O 1,1

%A _N. J. A. Sloane_, Mar 13 2013

%E More terms from _Alois P. Heinz_, Mar 13 2013