A118179 Numbers which occur only once in A005229.
2, 4, 5, 8, 9, 11, 13, 14, 15, 18, 21, 22, 23, 25, 27, 28, 31, 32, 33, 34, 35, 38, 40, 41, 42, 44, 47, 48, 49, 50, 51, 52, 55, 56, 57, 60, 61, 62, 65, 67, 68, 70, 71, 72, 73, 74, 75, 76, 79, 82, 83, 84, 86, 88, 89, 90, 91, 96, 98, 99, 100, 101, 103, 104, 105, 106, 107, 108
Offset: 1
Keywords
Examples
1, 3, 6 and 7 occur twice in A005229, so these numbers are not in the sequence.
Programs
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Mathematica
terms = 70; Clear[b, f]; b[1] = b[2] = 1; b[n_] := b[n] = b[b[n - 2]] + b[n - b[n - 2]]; f[max_] := f[max] = PadRight[Select[Tally[Array[b, max]], #[[2]] == 1 &][[All, 1]], terms]; f[max = terms]; f[max = max + terms]; While[f[max] != f[max - terms], max = max + terms]; A118179 = f[max](* Jean-François Alcover, Oct 12 2017 *)
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PARI
{m=156;v=vector(m);v[1]=1;v[2]=1;for(n=3,m,v[n]=v[v[n-2]]+v[n-v[n-2]]); i=1;k=1;while(i<=m,c=0;while(i<=m&&v[i]==k,c++;i++);if(i<=m&&c==1,print1(k,","));k++)}