A262359 Numbers k such that denominator(sigma(k)/k) = 6.

18, 22932, 14520576, 1610563584, 1907020800, 2836487808, 6399679104, 70912195200, 82819376640, 159991977600, 2732372020224, 6164773235712, 68309300505600, 148068998977536, 154119330892800, 264727305267840, 649657533767040, 3701724974438400, 42503412523106304, 220312341220608000

Offset

1,1

Links

David A. Corneth, Table of n, a(n) for n = 1..54 (terms <= 10^28)

Example

sigma(18)/18 = 13/6, hence 18 is a term.

Prog

(PARI) isok(n) = denominator(sigma(n, -1)) == 6;
(PARI) lista(nn) = {k = 6; nb = 0; while (nb != nn, if (denominator(sigma(k, -1)) == 6, print1(k, ", "); nb++); k += 6; ); }

Crossrefs

Cf. similar sequences with A017666(n)=k: A159907 (k=2), A245775 (k=3), A229088 (k=4), A067237 (k=5).

Cf. A000203.

Sequence in context: A201986 A153301 A129042 * A202155 A296653 A255406

Adjacent sequences: A262356 A262357 A262358 * A262360 A262361 A262362

Keyword

nonn

Author

Michel Marcus, Sep 19 2015

Extensions

a(10)-a(12) from Jud McCranie, Oct 14 2023

More terms from David A. Corneth, Oct 15 2023

Status

approved