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A068090
Numbers n which divide the right concatenation of the first n even numbers.
0
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
1,2
EXAMPLE
The right concatenation of the first six even numbers is 24681012 and 6 divides this number. So 6 is a member of the sequence.
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 *)
CROSSREFS
Cf. A029455.
Sequence in context: A248888 A112587 A372916 * A172121 A094222 A164043
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Feb 19 2002
EXTENSIONS
Edited and extended by James A. Sellers, Feb 20, 2002
Offset corrected by Sean A. Irvine, Jan 25 2024
STATUS
approved