A333053 Numbers m such that min(d(m), d(m+1)) > min(d(k), d(k+1)) for all k < m, where d(m) is the number of divisors of m (A000005).

1, 2, 8, 14, 44, 104, 224, 495, 735, 2024, 2079, 5264, 5984, 21735, 126224, 201824, 862784, 1890944, 2821455, 6116175, 7316000, 14753024, 23014719, 38127375, 80061344, 205466624, 391738599, 879207615, 1794220064, 3199900599, 3809727999, 16916370624

Offset

1,2

Comments

The corresponding values of min(d(a(n)), d(a(n)+1)) are 1, 2, 3, 4, 6, 8, 9, 10, 12, 15, 16, 20, 24, 32, 40, 48, 56, 64, 72, 80, 96, 108, 112, 120, 144, 160, 192, 224, 240, 256, 288, 320, ...

Links

Table of n, a(n) for n=1..32.

Example

The values of min(d(k), d(k+1)) for k = 1, 2, ... 8 are 1, 2, 2, 2, 2, 2, 2, 3. The record values in this range, 1, 2 and 3, are obtained at k = 1, 2, and 8.

Mathematica

seq={}; dminmax = 0; d1 = 1; Do[d2 = DivisorSigma[0, n]; dmin = Min[d1, d2]; If[dmin > dminmax, dminmax = dmin; AppendTo[seq, n-1]]; d1 = d2, {n, 2, 10^6}]; seq

Crossrefs

Cf. A000005, A002182, A123000, A175143, A333054.

Sequence in context: A333575 A259119 A039660 * A333054 A119752 A111001

Adjacent sequences: A333050 A333051 A333052 * A333054 A333055 A333056

Keyword

nonn,more

Author

Amiram Eldar, Mar 06 2020

Status

approved