A068090 Numbers n which divide the right concatenation of the first n even numbers.

1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 15, 18, 20, 24, 25, 30, 35, 36, 39, 40, 45, 50, 60, 72, 75, 80, 90, 100, 120, 125, 144, 150, 180, 200, 204, 225, 240, 250, 300, 360, 375, 400, 450, 500, 507, 540, 585, 600, 624, 625, 675, 702, 720, 750, 780, 800, 804, 864, 900

Offset: 1

Author

Amarnath Murthy, Feb 19 2002

Keywords

• base
• easy
• nonn

Examples

			The right concatenation of the first six even numbers is 24681012 and 6 divides this number. So 6 is a member of the sequence.
		

Crossrefs

Cf. A029455.

Programs

Maple

a := proc(n): if n=1 then RETURN(2) fi: 2*n+a(n-1)*10^(ceil(log[10](2*n+.01))) end: for n from 1 to 1000 do if a(n) mod n = 0 then printf(`%d,`,n) fi; od:

Mathematica

concat[n_]:=FromDigits[Flatten[IntegerDigits/@Range[2,2n,2]]]; Select[ Range[700],Divisible[concat[#],#]&] (* Harvey P. Dale, Nov 02 2011 *)

Extensions

Edited and extended by James Sellers, Feb 20 2002

Offset corrected by Sean A. Irvine, Jan 25 2024