A072724 Integers which are exactly the concatenation of the first m even numbers (A019520) divided by their sum (A002378 = m^2+m).

1, 4, 8227, 3427918353

Offset

1,2

Comments

A probability argument suggests that this sequence may be finite.

Links

Table of n, a(n) for n=1..4.

Example

a(1) = 2/2 =1; a(2) = 24/(2+4) = 4; a(3) = 246810/(2+4+6+8+10) = 8227; a(4) = 246810121416/(2+4+6+8+10+12+14+16).

Mathematica

With[{eds=Range[2, 1500, 2]}, Select[Table[FromDigits[Flatten[ IntegerDigits/@ Take[eds, n]]]/Total[Take[eds, n]], {n, 502}], IntegerQ]] (* Harvey P. Dale, Nov 29 2011 *)

Crossrefs

Cf. A067121, A072723, A072725.

Sequence in context: A053951 A058460 A115050 * A116271 A274551 A257281

Adjacent sequences: A072721 A072722 A072723 * A072725 A072726 A072727

Keyword

base,nonn

Author

Henry Bottomley, Jul 06 2002

Status

approved