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a(n) = the n-th positive integer which is missing from A134624.
1

%I #16 Sep 25 2024 01:52:23

%S 2,3,5,7,8,9,11,12,13,15,17,19,20,21,23,25,28,29,30,31,32,33,35,36,37,

%T 39,41,43,44,45,47,48,49,51,53,54,55,56,57,59,61,63,65,67,68,69,71,73,

%U 76,77,78,79,80,81,83,84,85,87,89,91,92,93,95,97,100,101,102

%N a(n) = the n-th positive integer which is missing from A134624.

%C A134624(1) = 1. A134624(n) is the smallest integer which is > A134624(n-1) and is different from and not coprime to a(n-1). [corrected by _Michel Marcus_, Sep 06 2019]

%o (PARI) missing(n, v) = {my(nb = 0, k = 1, s = Set(v), ok = 0); while(!ok, if (! setsearch(s, k), nb++); ok = (nb == n); if (!ok, k++);); k;}

%o nextt(start, cop) = {my(k = max(start+1, cop+1)); while(gcd(k, cop) == 1, k++); k;}

%o list3(nn) = {my(v3 = vector(nn), v4 = vector(nn)); v4[1] = 1; for (n=1, nn, v3[n] = missing(n, v4); if (n+1 > nn, break); v4[n+1] = nextt(v4[n], v3[n]);); v3} \\ _Michel Marcus_, Sep 06 2019

%Y Cf. A053661, A134624.

%K nonn

%O 1,1

%A _Leroy Quet_, Nov 04 2007

%E More terms from _Michel Marcus_, Sep 06 2019