login
Differences between successive numbers whose sum of digits in base 3 is 2.
2

%I #14 Jul 04 2019 11:52:10

%S 2,2,2,4,2,6,10,2,6,18,28,2,6,18,54,82,2,6,18,54,162,244,2,6,18,54,

%T 162,486,730,2,6,18,54,162,486,1458,2188,2,6,18,54,162,486,1458,4374,

%U 6562,2,6,18,54,162,486,1458,4374,13122

%N Differences between successive numbers whose sum of digits in base 3 is 2.

%C First differences of A052216 when the entries in that sequence are interpreted as base 3 numbers.

%C Can be regarded as a triangle, where T(0,0)=2, T(n+1,0) = T(n,0)+T(n,n), T(n+1,m) = T(n,m) for 0 < m <= n and T(n+1,n+1) = sum of T(n+1,0..n)

%H G. C. Greubel, <a href="/A135293/b135293.txt">Table of n, a(n) for the first 50 rows</a>

%F T(n,m) = 2*3^(m-1) = A025192(m) for m>0. T(n,0) = 2*A124302(n). - _Franklin T. Adams-Watters_, Sep 29 2011

%e triangle begins:

%e 2

%e 2 2

%e 4 2 6

%e 10 2 6 18

%e 28 2 6 18 54

%e 82 2 6 18 54 162

%e 244 2 6 18 54 162 486.

%t T[0, 0] := 2; T[n_, 0] := 3^(n - 1) + 1; T[n_, m_] := 2*3^(m - 1); Table[T[n, m], {n, 0, 5}, {m, 0, n}] (* _G. C. Greubel_, Oct 09 2016 *)

%t Join[{2},Differences[Select[Range[50000],Total[IntegerDigits[#,3]]==2&]]] (* _Harvey P. Dale_, Jul 04 2019 *)

%Y Cf. A052216.

%K nonn,tabl,base

%O 0,1

%A Adam Shelly (adam.shelly(AT)gmail.com), Dec 04 2007, Dec 05 2007

%E Edited by _Franklin T. Adams-Watters_, Sep 29 2011