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

Author

Rémy Sigrist, Dec 04 2022

Keywords

• nonn
• look

Examples

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

Links

• Rémy Sigrist, PARI program
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A000124, A076034.

Programs

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

PARI

See Links section.

Formula

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

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