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A068517 a(2n) = concatenation of 4n+1 and 4n+2, a(2n+1) = concatenation of the two most nearly equal numbers whose product is a(2n). 0
12, 34, 56, 78, 910, 2635, 1314, 1873, 1718, 2859, 2122, 21061, 2526, 6421, 2930, 10293, 3334, 21667, 3738, 4289, 4142, 38109, 4546, 22273, 4950, 6675, 5354, 22677, 5758, 22879, 6162, 7879, 6566, 6798, 6970, 8285, 7374, 61229, 7778, 23889, 8182 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
EXAMPLE
a(6) = 1314 = 2*3^2*73 = 18*73; a(7) = 1873.
MATHEMATICA
conc[m_, n_] := FromDigits[Join[IntegerDigits[m], IntegerDigits[n]]]; a[n_] := If[EvenQ[n], conc[2n+1, 2n+2], l=Length[ds=Divisors[a[n-1]]]; conc[ds[[l/2]], ds[[1+l/2]]]]
CROSSREFS
Sequence in context: A077295 A030655 A098080 * A113748 A069125 A142245
KEYWORD
nonn,base,easy
AUTHOR
Jon Kongsvold (Jon.Kongsvold(AT)idi.ntnu.no) and Martin Ystenes, Mar 19 2002
EXTENSIONS
More terms from Sascha Kurz, Feb 12 2003
STATUS
approved

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Last modified March 1 04:59 EST 2024. Contains 370430 sequences. (Running on oeis4.)