

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
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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

N. J. A. Sloane


EXTENSIONS

More terms from Erich Friedman
Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar


STATUS

approved



