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A299410
Numbers that can be expressed both as the sum of first deficient numbers and as the sum of first abundant numbers.
0
30, 8388, 10093090395, 107318445076, 123649798600, 28404836330575, 85678144827202815, 456013868127570451
OFFSET
1,1
COMMENTS
Intersection of A173106 and A173107.
EXAMPLE
The first seven deficient numbers sum to 1 + 2 + 3 + 4 + 5 + 7 + 8 = 30 and the first two abundant numbers sum to 12 + 18 = 30.
The sum of first 113 deficient numbers and the sum of first 61 abundant numbers are equal to 8388.
MAPLE
with(numtheory): P:=proc(q) local a, b, c, d, n; a:=0; b:=0; c:=0; d:=0;
for n from 1 to q do b:=b+1; while sigma(b)<=2*b do b:=b+1; od; a:=a+b;
while c<a do d:=d+1; if sigma(d)<2*d then c:=c+d; fi; od;
if c=a then print(a); fi; od; end: P(10^9);
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Feb 26 2018
EXTENSIONS
a(6)-a(8) from Giovanni Resta, Feb 26 2018
STATUS
approved