A061085 - OEIS

%I #8 Aug 04 2015 23:36:46

%S 4,8,12,16,170,204,238,272,306,340,374,408,442,476,510,544,578,612,

%T 646,680,714,748,782,816,850,884,918,952,986,1020,1054,1088,1122,1156,

%U 1190,1224,1258,1292,1326,1360,1394,1428,1462,1496,1530,1564,1598,1632,1666

%N a(n) = A019550(n) / 3.

%H Amarnath Murthy, <a href="http://fs.gallup.unm.edu/MurthyBook.pdf">Some propositions on Smarandache n2n sequence</a>, Smarandache Notions Journal, Digital Library of Science, p 126

%H Felice Russo, <a href="http://fs.gallup.unm.edu/Felice-Russo-book1.pdf">A set of new Smarandache Functions, Sequences and conjectures in number theory</a>, Smarandache Notions Journal, Digital Library of Science, (2000)

%F a(n) = one-third of the number obtained by concatenating n with 2n.

%e a(8) = 272 = 816/3, where 816 is 8 concatenated with 16.

%p cat2 := proc(a,b) dgsb := max(1,ilog10(b)+1) ; a*10^dgsb+b ; end proc:

%p A019550 := proc(n) cat2(n,2*n) ; end proc:

%p A061085 := proc(n) A019550(n)/3 ; end proc: seq(A061085(n),n=1..80) ; # _R. J. Mathar_, Oct 10 2010

%t Table[FromDigits[Join[IntegerDigits[n],IntegerDigits[2n]]]/3,{n,50}] (* _Harvey P. Dale_, Aug 18 2012 *)

%Y Cf. A019550.

%K nonn,base

%O 1,1

%A _Amarnath Murthy_, Apr 19 2001

%E Offset corrected and sequence extended by _R. J. Mathar_, Oct 10 2010