cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A154387 Composite numbers with even sum of digits.

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%I A154387 #13 Jan 07 2019 04:21:49
%S A154387 4,6,8,15,20,22,24,26,28,33,35,39,40,42,44,46,48,51,55,57,60,62,64,66,
%T A154387 68,75,77,80,82,84,86,88,91,93,95,99,105,110,112,114,116,118,121,123,
%U A154387 125,129,130,132,134,136,138,141,143,145,147,150,152,154,156,158,161
%N A154387 Composite numbers with even sum of digits.
%H A154387 Harvey P. Dale, <a href="/A154387/b154387.txt">Table of n, a(n) for n = 1..1000</a>
%e A154387 15 is composite and 1 + 5 = 6 (an even number), so 15 is a term;
%e A154387 20 is composite and 2 + 0 = 2 (an even number), so 20 is a term.
%p A154387 sd := proc (n) options operator, arrow: add(convert(n, base, 10)[j], j = 1 .. nops(convert(n, base, 10))) end proc: a := proc (n) if isprime(n) = false and `mod`(sd(n), 2) = 0 then n else end if end proc: seq(a(n), n = 2 .. 180); # _Emeric Deutsch_, Jan 17 2009
%t A154387 Select[Range[200],CompositeQ[#]&&EvenQ[Total[IntegerDigits[#]]]&] (* _Harvey P. Dale_, Aug 25 2016 *)
%Y A154387 Intersection of A002808 and A054683.
%K A154387 nonn,base
%O A154387 1,1
%A A154387 _Juri-Stepan Gerasimov_, Jan 08 2009
%E A154387 Replaced 45 by 46 - _R. J. Mathar_, Jan 12 2009
%E A154387 More terms from _Emeric Deutsch_, Jan 17 2009