cp's OEIS Frontend

A135548 Numbers in A134651 which are the sum of two terms from A001043 in a unique way.

%I A135548 #6 Oct 15 2013 03:36:55
%S A135548 10,13,16,17,20,23,24,26,29,30,32,35,38,41,44,47,50,57,64,65,68,70,73,
%T A135548 80,82,83,88,89,94,95,105,110,117,118,125,133,140,143,148,149,154,157,
%U A135548 167,176,177,178,182,191,192,200,203,208,209,215,221,227,236,242
%N A135548 Numbers in A134651 which are the sum of two terms from A001043 in a unique way.
%C A135548 Numbers that are the sum of two terms of A001043, but not sum of a different pair of two terms.
%e A135548 Recall that A001043 begins with 5,8,12,18,24,30,36,42,52,60,68,78,84,90, ...
%e A135548 So 48 is not in the sequence because 48 = 18+30 = 24+24.
%e A135548 But 88 is in the sequence as it is only = 52+36.
%e A135548 And 89 is there too because = 84+5.
%o A135548 (PARI) issum(i, vss) = {nb = 0; for (j = 1, #vss, if (vss[j] > i, break); for (k = 1, j, sv = vss[j] + vss[k]; if (sv == i, nb++); if (sv > i, break););); return (nb == 1);}
%o A135548 lista(nn) = {vec = vector(nn, i, i); vss = select(i->((precprime((i-1)/2) + nextprime(i/2) == i) && (i>2)), vec); for (i = 1, nn, if (issum(i, vss), print1(i, ", ")););} \\ _Michel Marcus_, Oct 14 2013
%Y A135548 Cf. A001043, A134651, A135045.
%K A135548 nonn
%O A135548 1,1
%A A135548 Zak Seidov, Feb 15 2008
%E A135548 Example, corrected and extended by _Michel Marcus_, Oct 14 2013