A067121 -id:A067121 - cp's OEIS frontend

A067122 Floor[X/Y] where X = concatenation of first n odd numbers in increasing order (A019519) and Y = their sum (A000290 = n^2).

1, 3, 15, 84, 543, 37719, 2771247, 212173614, 16764334957, 1357911131517, 112224060455966, 9429938413313834, 803497710956918416, 69281180179448577716, 6035160584520853881123, 530434035748903173145597

Offset: 1

Amarnath Murthy, Jan 08 2002

			a(4) = floor[1357/16] = floor[84.8125] =84.

Cf. A067112-A067121, A072723.

More terms from Henry Bottomley, Jul 07 2002

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

Original entry on oeis.org

1, 4, 8227, 3427918353

Offset: 1

Henry Bottomley, Jul 06 2002

A probability argument suggests that this sequence may be finite.

			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).

Cf. A067121, A072723, A072725.

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 *)

cp's OEIS Frontend

A067122 Floor[X/Y] where X = concatenation of first n odd numbers in increasing order (A019519) and Y = their sum (A000290 = n^2).

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

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Mathematica