A260988 - OEIS

A260988

Numbers n such that sigma(n) = m*sigma(n+2) with some m > 1.

8505, 25500, 30360, 37740, 40740, 123795, 141480, 185460, 442365, 485400, 834435, 953568, 1055460, 1097820, 1108320, 1397220, 1953960, 2088480, 2208840, 2571744, 3050784, 3342816, 3544695, 3810456, 4314156, 4725660, 4867236, 5638776, 6318180, 6596340, 8428320, 8630832, 9347280, 9576336, 9908460, 10271580, 10992360, 11789925

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OFFSET

1,1

COMMENTS

Sequence A227304 is the union of A055574 and { a(n)+1 }.

Many but not all terms are multiples of 5.

LINKS

Table of n, a(n) for n=1..38.

PROG

(PARI) for(n=1, 2e9, sigma(n)%sigma(n+2)||sigma(n)==sigma(n+2)||print1(n", "))

CROSSREFS

Cf. A000203, A055574, A067130, A058073.