A369271 The smallest positive number that has not yet appeared that is a multiple of the smallest prime that does not divide n.
2, 3, 4, 6, 8, 5, 10, 9, 12, 15, 14, 20, 16, 18, 22, 21, 24, 25, 26, 27, 28, 30, 32, 35, 34, 33, 36, 39, 38, 7, 40, 42, 44, 45, 46, 50, 48, 51, 52, 54, 56, 55, 58, 57, 60, 63, 62, 65, 64, 66, 68, 69, 70, 75, 72, 78, 74, 81, 76, 49, 80, 84, 82, 87, 86, 85, 88, 90, 92, 93, 94, 95, 96, 99, 98
Offset: 1
Keywords
Examples
a(7) = 10 as 2 is the smallest prime that does not divide 7, and 10 = 2*5 is the smallest multiple of 2 that has not yet appeared.
Links
- Scott R. Shannon, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
nn = 2^10; c[] := False; m[] := 1; f[x_] := Block[{q = 2}, While[Divisible[x, q], q = NextPrime[q]]; q]; Do[While[c[Set[k, #*m[#]]], m[#]++] &[f[i]]; Set[{a[i], c[k]}, {k, True}], {i, nn}]; Array[a, nn] (* Michael De Vlieger, Jan 24 2024 *)
Formula
a(A002110(k-1)) = the k-th prime.
Comments