A247034 Smallest integer x such that the number of integers y<x satisfying sigma(y)/y > sigma(x)/x is exactly n.

1, 3, 10, 5, 9, 7, 15, 32, 132, 11, 21, 13, 44, 70, 52, 17, 25, 19, 38, 33, 198, 23, 35, 46, 39, 76, 234, 29, 220, 31, 224, 62, 51, 136, 260, 37, 57, 55, 74, 41, 1170, 43, 196, 82, 69, 47, 10440, 154, 222, 94, 520, 53, 744, 148, 77, 190, 87, 59, 182, 61, 93

Offset

0,2

Comments

Conjecture: a(n) exists for all n.

Links

Amiram Eldar, Table of n, a(n) for n = 0..421

Prog

(PARI) lista(nn) = {v = vector(nn, n, sigma(n)/n); vmore = vector(nn+1); for (n=1, nn, nb = sum(i=1, n, v[i] > v[n]); if (vmore[nb+1] == 0, vmore[nb+1] = n); ); for (i=1, #vmore, if (!vmore[i], break, print1(vmore[i], ", "))); }

Crossrefs

Cf. A000203 (sigma), A004394 (superabundant), A017665 and A017666 (sigma(n)/n).

Cf. A247015.

Sequence in context: A111229 A100984 A045985 * A275511 A035411 A033478

Adjacent sequences: A247031 A247032 A247033 * A247035 A247036 A247037

Keyword

nonn

Author

Michel Marcus, Sep 10 2014

Status

approved