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A118735 Numbers n such that 2^n and 3^n have odd digit sum. 3

%I #10 Jun 05 2021 19:20:48

%S 0,4,5,10,16,18,20,22,25,27,30,31,34,35,39,48,52,53,59,62,63,66,68,69,

%T 81,87,89,92,99,100,101,105,108,114,118,119,121,127,131,133,141,145,

%U 146,150,153,158,159,160,165,167,169,175,186,188,191,196,197,201,202,203

%N Numbers n such that 2^n and 3^n have odd digit sum.

%H Harvey P. Dale, <a href="/A118735/b118735.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[0, 206], And @@ ((Mod[ Plus @@ IntegerDigits[ # ], 2] == 1 &) /@ {2^#, 3^#}) &] (* _Ray Chandler_, Jun 10 2006 *)

%t odsQ[n_]:=AllTrue[Total[IntegerDigits[#]]&/@{2^n,3^n},OddQ]; Select[ Range[ 0,250],odsQ] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 05 2021 *)

%Y Cf. Intersection of A118731 and A118732.

%K base,nonn

%O 1,2

%A _Zak Seidov_, May 22 2006

%E Extended by _Ray Chandler_, Jun 10 2006

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Last modified April 25 05:18 EDT 2024. Contains 371964 sequences. (Running on oeis4.)