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This sequence is constructed using only the four single-digit primes 2,3,5,7 in that order.
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%I #22 Dec 08 2018 04:35:00

%S 2,23,235,2357,23572,235723,2357235,23572357,235723572,2357235723

%N This sequence is constructed using only the four single-digit primes 2,3,5,7 in that order.

%C The idea for the sequence came from the way long DNA sequences are produced from only four bases, namely, A,T,G,C. Nature is able to produce remarkable species on Earth by permuting these four bases in an apparent random order. The connection between the arrangement of DNA bases in the chromosomes of species and the number system is poorly understood.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (10,0,0,1,-10)

%F G.f.: x*(2 + 3*x + 5*x^2 + 7*x^3) / ( (x-1)*(10*x-1)*(1+x)*(1+x^2) ). - _R. J. Mathar_, Feb 03 2011

%t CoefficientList[Series[x (2+3x+5x^2+7x^3)/((x-1)(10x-1) (1+x)(1+x^2)),{x,0,50}],x] (* _Harvey P. Dale_, Mar 20 2011 *)

%Y Cf. A019518.

%K nonn,base

%O 1,1

%A _Parthasarathy Nambi_, Sep 30 2004