cp's OEIS Frontend

A376257 a(n) = (n - c(n))*(-1)^c(n), where c(n) is the product of the digits of n (A007954).

%I A376257 #24 Dec 10 2024 10:26:23
%S A376257 0,0,0,0,0,0,0,0,0,10,-10,10,-10,10,-10,10,-10,10,-10,20,19,18,17,16,
%T A376257 15,14,13,12,11,30,-28,26,-24,22,-20,18,-16,14,-12,40,37,34,31,28,25,
%U A376257 22,19,16,13,50,-46,42,-38,34,-30,26,-22,18,-14,60,55,50,45,40,35,30,25,20,15,70,-64,58
%N A376257 a(n) = (n - c(n))*(-1)^c(n), where c(n) is the product of the digits of n (A007954).
%C A376257 There is an interesting pattern on the graph of the sequence.
%H A376257 Paolo Xausa, <a href="/A376257/b376257.txt">Table of n, a(n) for n = 1..10000</a>
%F A376257 a(n) = (n-A007954(n)) * (-1)^A007954(n).
%e A376257 For n = 129: 1*2*9=18. So a(n) = (129-18)*(-1)^18 = 111.
%t A376257 A376257[n_] := (n - #)*(-1)^# & [Times @@ IntegerDigits[n]];
%t A376257 Array[A376257, 100] (* _Paolo Xausa_, Dec 10 2024 *)
%Y A376257 Cf. A007954, A070565.
%K A376257 sign,base,look
%O A376257 1,10
%A A376257 _Stuart Coe_, Sep 17 2024