Search: id:A106708
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%I A106708
%S A106708 0,0,0,2,0,23,0,24,3,25,0,2346,0,27,35,248,0,2369,0,24510,37,211,0,
%T A106708 2346812,5,213,39,24714,0,23561015,0,24816,311,217,57,234691218,0,219,
%U A106708 313,24581020,0,23671421,0,241122,35915,223,0,23468121624,7,251025,317
%N A106708 Replace n by the concatenation of its proper divisors (a(n) = 0 unless 
               n is composite).
%H A106708 Klaus Brockhaus, <a href="b106708.txt">Table of n, a(n) for n=1..5000</
               a>
%F A106708 a(n) = A037279(n)*A010051(n). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Aug 01 2007
%p A106708 A106708 := proc(n) local dvs ; if isprime(n) or n = 1 then 0; else dvs 
               := [op(numtheory[divisors](n) minus {1,n} )] ; dvs := sort(dvs) ; 
               cat(op(dvs)) ; fi ; end: seq(A106708(n),n=1..80) ; - R. J. Mathar 
               (mathar(AT)strw.leidenuniv.nl), Aug 01 2007
%o A106708 (PARI) {map(n) = local(d); d=divisors(n); if(#d<3, 0, d[1]=""; eval(concat(vecextract(d, 
               concat("..", #d-1)))))} for(n=1,51,print1(map(n),",")) /* Klaus Brockhaus, 
               Aug 05 2007 */
%Y A106708 Cf. A037278, A120712, A037279, A131983 (records), A131984 (where records 
               occur).
%Y A106708 Sequence in context: A139003 A156438 A009378 this_sequence A138551 A133490 
               A051728
%Y A106708 Adjacent sequences: A106705 A106706 A106707 this_sequence A106709 A106710 
               A106711
%K A106708 nonn,base
%O A106708 1,4
%A A106708 N. J. A. Sloane (njas(AT)research.att.com), Jul 20 2007
%E A106708 More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl) and Klaus 
               Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 01 2007

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