A385398 Numbers m >= 1 such that Sum_{k = 1..m} gcd(m, floor(m / k)) > Sum_{k = 1..m} gcd(m, ceiling(m / k)).

407, 539, 559, 637, 671, 793, 803, 949, 1037, 1067, 1159, 1241, 1273, 1331, 1469, 1649, 1679, 1727, 1817, 1843, 1853, 1919, 2057, 2159, 2197, 2231, 2299, 2321, 2507, 2651, 2669, 2743, 2783, 2813, 2873, 2983, 2987, 3007, 3077, 3133, 3161, 3179, 3193, 3211, 3379

Offset

1,1

Links

Table of n, a(n) for n=1..45.

Example

m = 407: Sum_{k = 1..407} gcd(407, floor(407 / k)) = 909, Sum_{k = 1..407} gcd(407, ceiling(407 / k)) = 899, 909 > 899, thus m = 407 is a term.

Prog

(PARI) isok(m) = sum(k=1, m, gcd(m, floor(m/k))) > sum(k=1, m, gcd(m, ceil(m/k))); \\ Michel Marcus, Jun 28 2025

Crossrefs

Cf. A018804, A384628, A385402.

Sequence in context: A172891 A172921 A063138 * A118327 A213606 A343157

Adjacent sequences: A385395 A385396 A385397 * A385399 A385400 A385401

Keyword

nonn

Author

Ctibor O. Zizka, Jun 27 2025

Status

approved