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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
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
Sequence in context: A157486 A086476 A279621 * A151721 A187743 A251829
KEYWORD
nonn
AUTHOR
STATUS
approved

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