A072723 Integers which are exactly the concatenation of the first m odd numbers (A019519) divided by their sum (A000290 = m^2).

1, 15, 16764334957, 3079163563531047898532266016633501

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) = 1/1 = 1; a(2) = 135/(1+3+5) = 15; a(3) = 1357911131517/(1+3+5+7+9+11+13+15+17) = 16764334957; a(4) = 1357911131517192123252729313335373941/(1+3+5+7+9+11+13+15+17+19+21+23+25+27+29+31+33+35+37+39+41) = 3079163563531047898532266016633501.

Mathematica

Select[Table[FromDigits[Flatten[IntegerDigits/@Range[1, 2n+1, 2]]]/Total[Range[1, 2n+1, 2]], {n, 0, 30}], IntegerQ] (* Harvey P. Dale, Mar 24 2023 *)

Crossrefs

Cf. A067122, A072724, A072725.

Sequence in context: A068252 A115242 A296528 * A111413 A181029 A072838

Adjacent sequences: A072720 A072721 A072722 * A072724 A072725 A072726

Keyword

base,nonn

Author

Henry Bottomley, Jul 06 2002

Status

approved