

A299410


Numbers that can be expressed both as the sum of first deficient numbers and as the sum of first abundant numbers.


0




OFFSET

1,1


COMMENTS

Intersection of A173106 and A173107.


LINKS

Table of n, a(n) for n=1..8.


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

Cf. A005100, A005101, A173106, A173107.
Sequence in context: A239925 A059049 A056071 * A294976 A294975 A294979
Adjacent sequences: A299407 A299408 A299409 * A299411 A299412 A299413


KEYWORD

nonn,more


AUTHOR

Paolo P. Lava, Feb 26 2018


EXTENSIONS

a(6)a(8) from Giovanni Resta, Feb 26 2018


STATUS

approved



