A067122
Floor[X/Y] where X = concatenation of first n odd numbers in increasing order (A019519) and Y = their sum (A000290 = n^2).
Original entry on oeis.org
1, 3, 15, 84, 543, 37719, 2771247, 212173614, 16764334957, 1357911131517, 112224060455966, 9429938413313834, 803497710956918416, 69281180179448577716, 6035160584520853881123, 530434035748903173145597
Offset: 1
a(4) = floor[1357/16] = floor[84.8125] =84.
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
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).
-
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 *)
A072725
Integers which are exactly the concatenation of the first m numbers (A007908) divided by their sum (A000217 = m*(m+1)/2).
Original entry on oeis.org
a(1) = 1/1 =1; a(2) = 12/(1+2) = 4; a(3) = 12345/(1+2+3+4+5).
Showing 1-3 of 3 results.
Comments