A357764 Numbers m such that A357761(m) < A357761(k) for all k < m.

1, 3, 9, 15, 30, 60, 90, 180, 360, 540, 720, 1080, 2160, 4320, 6120, 8640, 12240, 18360, 24480, 36720, 73440, 146880, 257040, 293760, 514080, 587520, 807840, 1028160, 1615680, 1884960, 2056320, 2827440, 3231360, 3769920, 5654880, 7539840, 9424800, 11309760, 18849600

Offset: 1

Author

Amiram Eldar, Oct 12 2022

Keywords

• nonn
• base

Comments

Since A357761(15*2^n) = -2*(n+1), A357761 is unbounded from below and this sequence is infinite.

The corresponding records of low value are 1, 0, -1, -2, -4, -6, -8, -12, -16, -18, -20, -24, -30, -36, ... .

Crossrefs

Cf. A355969, A356020, A357761, A357763.

Programs

Mathematica

f[n_] := -DivisorSum[n, (-1)^DigitCount[#, 2, 1] &]; fm = 2; s = {}; Do[f1 = f[n]; If[f1 < fm, fm = f1; AppendTo[s, n]], {n, 1, 10^5}]; s

PARI

f(n) = -sumdiv(n, d, (-1)^hammingweight(d));
lista(nmax) = {my(fm = 2); for(n = 1, nmax, f1 = f(n); if(f1 < fm, fm = f1; print1(n, ", ")))};