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 A037279 If n is composite, replace n with the concatenation of its proper divisors, otherwise a(n) = n. 6
 1, 2, 3, 2, 5, 23, 7, 24, 3, 25, 11, 2346, 13, 27, 35, 248, 17, 2369, 19, 24510, 37, 211, 23, 2346812, 5, 213, 39, 24714, 29, 23561015, 31, 24816, 311, 217, 57, 234691218, 37, 219, 313, 24581020, 41, 23671421, 43, 241122, 35915, 223, 47, 23468121624, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE Divisors of 12 are 1,2,3,4,6,12, so a(12)=2346. MAPLE A037279 := proc(n) local dvs ; if isprime(n) or n = 1 then n; else dvs := [op(numtheory[divisors](n) minus {1, n} )] ; dvs := sort(dvs) ; cat(op(dvs)) ; fi ; end: seq(A037279(n), n=1..80) ; # R. J. Mathar, Jul 23 2007 MATHEMATICA f[n_]:=If[PrimeQ[n], n, FromDigits[Flatten[IntegerDigits/@Rest[ Most[ Divisors[n]]]]]]; Join[{1}, Array[f, 50, 2]] (* Harvey P. Dale, Sep 24 2012 *) CROSSREFS Cf. A037278, A120712, A106708. Sequence in context: A120716 A084318 A084317 * A163591 A085307 A078599 Adjacent sequences:  A037276 A037277 A037278 * A037280 A037281 A037282 KEYWORD nonn,base AUTHOR EXTENSIONS More terms from Erich Friedman Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar STATUS approved

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Last modified December 12 22:57 EST 2018. Contains 318081 sequences. (Running on oeis4.)