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A143712 Numbers with at least two digits in which all digits except the rightmost are even and the rightmost is odd. 2

%I #24 Aug 06 2022 18:54:48

%S 21,23,25,27,29,41,43,45,47,49,61,63,65,67,69,81,83,85,87,89,201,203,

%T 205,207,209,221,223,225,227,229,241,243,245,247,249,261,263,265,267,

%U 269,281,283,285,287,289,401,403,405,407,409,421,423,425,427,429,441,443,445,447

%N Numbers with at least two digits in which all digits except the rightmost are even and the rightmost is odd.

%C These are called e-type numbers, cf. A163396.

%H Harvey P. Dale, <a href="/A143712/b143712.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Ca#CARRYLESS">Index entries for sequences related to carryless arithmetic</a>

%t Select[Range[21, 500], (id = IntegerDigits[#1]; And @@ EvenQ /@ Most[id] && OddQ[Last[id]]) & ] (* _Jean-François Alcover_, May 23 2013 *)

%t eodQ[n_]:=Module[{td=TakeDrop[IntegerDigits[n],-1]},OddQ[td[[1,1]]]&&AllTrue[ td[[2]],EvenQ]]; Select[Range[10,500],eodQ] (* _Harvey P. Dale_, Aug 06 2022 *)

%Y Cf. A144162, A163396, A169984.

%K nonn,base

%O 1,1

%A _David Applegate_, _Marc LeBrun_ and _N. J. A. Sloane_, Aug 24 2010

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Last modified April 19 09:23 EDT 2024. Contains 371782 sequences. (Running on oeis4.)