A358874 Inverse permutation to A076034.

1, 2, 3, 4, 5, 7, 6, 11, 12, 16, 8, 22, 9, 29, 30, 37, 10, 46, 13, 56, 17, 67, 14, 79, 15, 92, 38, 106, 18, 121, 19, 137, 57, 154, 23, 172, 20, 191, 68, 211, 21, 232, 24, 254, 93, 277, 25, 301, 39, 326, 107, 352, 26, 379, 40, 407, 138, 436, 27, 466, 28, 497

Offset

1,2

Links

Table of n, a(n) for n=1..62.

Rémy Sigrist, PARI program

Index entries for sequences that are permutations of the natural numbers

Formula

a(2*n) = A000124(n).

a(p) < a(n) if p < n with p a prime number.

Example

A076034(42) = 101, so a(101) = 42.

Maple

S:=[$1..10000]:
V:= Vector(10000): ok:= true;
for n from 1 while ok do
  A:= [S[1]]; R:= 1; count:= 1;
  for k from 2 while count < n do
    if k > nops(S) then ok:= false; break fi;
    if andmap(t -> igcd(t, S[k])=1, A) then count:= count+1; A:= [op(A), S[k]]; R:= R, k; fi
  od;
  S:= subsop(op(map(t -> t=NULL, [R])), S);
  for i from 1 to nops(A) do
    V[A[i]]:= n*(n-1)/2+i
  od
od:
if member(0, V, 'q') then convert(V[1..q-1], list)
else convert(V, list)
fi; # Robert Israel, Dec 04 2022

Prog

(PARI) See Links section.

Crossrefs

Cf. A000124, A076034.

Sequence in context: A278505 A278506 A255546 * A080688 A082025 A076034

Adjacent sequences: A358871 A358872 A358873 * A358875 A358876 A358877

Keyword

nonn,look

Author

Rémy Sigrist, Dec 04 2022

Status

approved