A347350 - OEIS

A347350

Sequence obtained by writing the first 4 integers and skipping 1, then writing the next 5 integers and skipping 2, then writing the next 6 and skipping 3, etc.

%I #13 Aug 31 2021 01:13:09

%S 1,2,3,4,6,7,8,9,10,13,14,15,16,17,18,22,23,24,25,26,27,28,33,34,35,

%T 36,37,38,39,40,46,47,48,49,50,51,52,53,54,61,62,63,64,65,66,67,68,69,

%U 70,78,79,80,81,82,83,84,85,86,87,88,97,98,99,100,101,102,103,104,105

%N Sequence obtained by writing the first 4 integers and skipping 1, then writing the next 5 integers and skipping 2, then writing the next 6 and skipping 3, etc.

%H Ana Rechtman, <a href="http://images.math.cnrs.fr/Aout-2021-4e-defi.html">Août 2021, 4e défi</a>, Images des Mathématiques, CNRS, 2021.

%H <a href="/index/Si#sieve">Index entries for sequences generated by sieves</a>

%o (PARI) lista(nn) = {my(va=[1..nn], list=List()); my(i=4, j=1, pos=1, ok=1); while (ok, for(m=1, i, if (pos > nn, ok=0, listput(list, va[pos])); pos++; ); pos += j; i++; j++;); Vec(list);}

%Y Cf. A004201, A004202, A048859.

%K nonn

%O 1,2

%A _Michel Marcus_, Aug 28 2021