A340303 Numbers k such that k and the next two numbers after k with the same prime signature as k also have the same set of distinct prime divisors as k.

10800, 12600, 54000, 75600, 148176, 162000, 264600, 324000, 609840, 453600, 529200, 793800, 444528, 648000, 1058400, 1323000, 1764000, 1620000, 2116800, 2646000, 2721600, 3704400, 3969000, 6403320, 4233600, 5292000, 4860000, 6223392, 7938000, 7408800, 8467200

Offset

1,1

Comments

Numbers k such that A007947(k) = A007947(A081761(k)) = A007947(A081761(A081761(k))).

Links

Table of n, a(n) for n=1..31.

Index entries for sequences related to prime signature

Example

10800 = 2^4 * 3^3 * 5^2 is a term since 10800 and the next two numbers with the same prime signature as 10800, 16200 = 2^3 * 3^4 * 5^2 and 18000 = 2^4 * 3^2 * 5^3, have the same set of distinct prime divisors, {2, 3, 5}.

Crossrefs

Subsequence of A340302.

Cf. A007947, A081761, A118914.

Sequence in context: A151935 A010089 A216142 * A093770 A190115 A203394

Adjacent sequences: A340300 A340301 A340302 * A340304 A340305 A340306

Keyword

nonn

Author

Amiram Eldar, Jan 03 2021

Status

approved