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A060469 Smallest positive a(n) such that number of solutions to a(n) = a(j)+a(k) j<k<n is one or less. 8

%I

%S 1,2,3,4,6,8,11,13,16,18,23,25,28,30,35,37,40,42,47,49,52,54,59,61,64,

%T 66,71,73,76,78,83,85,88,90,95,97,100,102,107,109,112,114,119,121,124,

%U 126,131,133,136,138,143,145,148,150,155,157,160,162,167,169,172,174

%N Smallest positive a(n) such that number of solutions to a(n) = a(j)+a(k) j<k<n is one or less.

%C Numbers {1,4,6,11} mod 12 plus {2,3,8}.

%H Colin Barker, <a href="/A060469/b060469.txt">Table of n, a(n) for n = 1..1000</a>

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

%F a(n) = a(n-1)+a(n-4)-a(n-5) for n>9. - _Colin Barker_, Feb 27 2015

%F G.f.: x*(2*x^10+x^8+x^7+2*x^6+x^5+x^4+x^3+x^2+x+1) / ((x-1)^2*(x+1)*(x^2+1)). - _Colin Barker_, Feb 27 2015

%e 11 is in the sequence since it is 3+8 but no other sum of two distinct terms.

%o (PARI) Vec(x*(2*x^10+x^8+x^7+2*x^6+x^5+x^4+x^3+x^2+x+1)/((x-1)^2*(x+1)*(x^2+1)) + O(x^100)) \\ _Colin Barker_, Feb 27 2015

%Y Cf. A002858, A033627, A060469, A060470, A060471, A060472.

%Y Virtually identical to A003662.

%K nonn,easy

%O 1,2

%A _Henry Bottomley_, Mar 15 2001

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Last modified August 20 06:02 EDT 2019. Contains 326139 sequences. (Running on oeis4.)