A380925 Integers k such that k = Sum k/(p_i + j), where p_i are the prime factors of k (with multiplicity). Case j = -4.

5, 75, 100, 343, 1125, 1500, 2000, 5145, 6860, 16875, 22500, 30000, 40000, 77175, 102900, 107653, 137200, 253125, 337500, 352947, 450000, 470596, 600000, 800000, 1157625, 1543500, 1614795, 2058000, 2153060, 2744000, 3796875, 5062500, 5294205, 6750000, 7058940

Offset

1,1

Links

Table of n, a(n) for n=1..35.

Example

337500 = 2^2*3^3*5^5 = 337500*2/(2-4) + 337500*3/(3-4) + 337500*5/(5-4)

Maple

with(numtheory): P:=proc(q, h) local k, n, v; v:=[];
for n from 1 to q do if n=add(n*k[2]/(k[1]+h), k=ifactors(n)[2]) then v:=[op(v), n];
fi; od; op(v); end: P(7058940, -4);

Crossrefs

Cf. A380888, A380889, A380900, A380901, A380923, A380924, A380926 - A380928.

Sequence in context: A355121 A376112 A156703 * A285452 A048350 A030991

Adjacent sequences: A380922 A380923 A380924 * A380926 A380927 A380928

Keyword

nonn,easy

Author

Paolo P. Lava, Mar 03 2025

Status

approved