|
%I #16 Mar 09 2023 09:03:27
%S 1,2,3,2,5,23,7,24,3,25,11,2346,13,27,35,248,17,2369,19,24510,37,211,
%T 23,2346812,5,213,39,24714,29,23561015,31,24816,311,217,57,234691218,
%U 37,219,313,24581020,41,23671421,43,241122,35915,223,47,23468121624,7
%N If n is composite, replace n with the concatenation of its nontrivial divisors, otherwise a(n) = n.
%H Harvey P. Dale, <a href="/A037279/b037279.txt">Table of n, a(n) for n = 1..1000</a>
%e Divisors of 12 are 1,2,3,4,6,12, so a(12)=2346.
%p 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
%t 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 *)
%Y Cf. A037278, A120712, A106708.
%K nonn,base
%O 1,2
%A _N. J. A. Sloane_
%E More terms from _Erich Friedman_
%E Edited by _N. J. A. Sloane_, Aug 29 2008 at the suggestion of _R. J. Mathar_
|
