A350314 The catch-up points of the Redstone permutation A350313.

2, 5, 11, 17, 23, 29, 37, 41, 47, 53, 59, 67, 71, 77, 83, 89, 97, 101, 107, 113, 119, 127, 131, 137, 143, 149, 157, 161, 167, 173, 179, 187, 191, 197, 203, 209, 221, 227, 233, 239, 247, 251, 257, 263, 269, 277, 281, 287, 293, 299, 307, 311, 317, 323, 329, 337

Offset

1,1

Comments

We say n is a 'catch-up point' of a permutation p of the positive integers if and only if p restricted to [n] = {1, 2, ..., n} is a permutation of [n].

The periodic structure of the first differences is described in A350315.

Links

Table of n, a(n) for n=1..56.

Mathematica

s = {2, 1}; c[_] = 0; Array[Set[c[s[[#]]], #] &, Length[s]]; j = Last[s]; u = 3; {2}~Join~Reap[Monitor[Do[If[j == u, While[c[u] > 0, u++]]; k = u; While[Nand[c[k] == 0, CoprimeQ[i, k], ! Divisible[i - 1, k]], k++]; If[k == u, Sow[i]]; Set[c[k], i]; j = k, {i, Length[s] + 1, 337}], i]][[-1, -1]] (* Michael De Vlieger, Dec 24 2021 *)

Crossrefs

Cf. A350313, A350315.

Sequence in context: A067775 A140552 A138644 * A164921 A156830 A140556

Adjacent sequences: A350311 A350312 A350313 * A350315 A350316 A350317

Keyword

nonn

Author

Peter Luschny, Dec 24 2021

Status

approved