cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A168226 Even numbers which are the sum of two odd abundant numbers.

This page as a plain text file.
%I A168226 #6 Jan 03 2013 20:03:50
%S A168226 1890,2520,3150,3780,4410,5040,5670,6300,6720,6930,7350,7380,7560,
%T A168226 7770,7980,8010,8190,8370,8400,8610,8640,8820,9000,9030,9240,9270,
%U A168226 9360,9450,9630,9660,9870,9900,9990,10080,10260,10290,10500,10530,10620,10710
%N A168226 Even numbers which are the sum of two odd abundant numbers.
%C A168226 Every even number >= 3706141025766237065507279802221127212928 is the sum of two odd abundant numbers. The largest even number which does not appear in this sequence is unknown.
%H A168226 Donovan Johnson, <a href="/A168226/b168226.txt">Table of n, a(n) for n = 1..1000</a>
%e A168226 945 is the smallest odd abundant number, so 945 + 945 = 1890 is the first term in the sequence.
%o A168226 (PARI) mx=66240; x=vector(mx); k=144; v=vector(k); c=0; forstep(i=945, mx-1, 2, if(sigma(i)-2*i>0, c++; v[c]=i)); for(i=1, k, for(j=i, k, s=v[i]+v[j]; if(s<=mx, x[s]=1, next(2)))); c=0; forstep(n=1890, mx, 2, if(x[n]==1, c++; write("b168226.txt", c " " n))) /* _Donovan Johnson_, Jan 03 2013 */
%Y A168226 Cf. A005231, A048260.
%K A168226 nonn
%O A168226 1,1
%A A168226 _William Rex Marshall_, Nov 20 2009