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.

A061085 a(n) = A019550(n) / 3.

Original entry on oeis.org

4, 8, 12, 16, 170, 204, 238, 272, 306, 340, 374, 408, 442, 476, 510, 544, 578, 612, 646, 680, 714, 748, 782, 816, 850, 884, 918, 952, 986, 1020, 1054, 1088, 1122, 1156, 1190, 1224, 1258, 1292, 1326, 1360, 1394, 1428, 1462, 1496, 1530, 1564, 1598, 1632, 1666
Offset: 1

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Author

Amarnath Murthy, Apr 19 2001

Keywords

Examples

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

Crossrefs

Cf. A019550.

Programs

  • Maple
    cat2 := proc(a,b) dgsb := max(1,ilog10(b)+1) ; a*10^dgsb+b ; end proc:
    A019550 := proc(n) cat2(n,2*n) ; end proc:
    A061085 := proc(n) A019550(n)/3 ; end proc: seq(A061085(n),n=1..80) ; # R. J. Mathar, Oct 10 2010
  • Mathematica
    Table[FromDigits[Join[IntegerDigits[n],IntegerDigits[2n]]]/3,{n,50}] (* Harvey P. Dale, Aug 18 2012 *)

Formula

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

Extensions

Offset corrected and sequence extended by R. J. Mathar, Oct 10 2010