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 A168226 Even numbers which are the sum of two odd abundant numbers. 2
 1890, 2520, 3150, 3780, 4410, 5040, 5670, 6300, 6720, 6930, 7350, 7380, 7560, 7770, 7980, 8010, 8190, 8370, 8400, 8610, 8640, 8820, 9000, 9030, 9240, 9270, 9360, 9450, 9630, 9660, 9870, 9900, 9990, 10080, 10260, 10290, 10500, 10530, 10620, 10710 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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. LINKS Donovan Johnson, Table of n, a(n) for n = 1..1000 EXAMPLE 945 is the smallest odd abundant number, so 945 + 945 = 1890 is the first term in the sequence. PROG (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 */ CROSSREFS Cf. A005231, A048260. Sequence in context: A157486 A086476 A279621 * A151721 A187743 A251829 Adjacent sequences: A168223 A168224 A168225 * A168227 A168228 A168229 KEYWORD nonn AUTHOR William Rex Marshall, Nov 20 2009 STATUS approved

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Last modified June 23 00:47 EDT 2024. Contains 373629 sequences. (Running on oeis4.)