OFFSET
1,3
COMMENTS
Conjecture: Every positive integer occurs in this sequence.
EXAMPLE
Corner of Gilbreath array:
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101
1 2 2 4 2 4 2 4 6 2 6 4 2 4 6 6 2 6 4 2 6 4 6 8 4 2
1 0 2 2 2 2 2 2 4 4 2 2 2 2 0 4 4 2 2 4 2 2 2 4 2 2
1 2 0 0 0 0 0 2 0 2 0 0 0 2 4 0 2 0 2 2 0 0 2 2 0 0
1 2 0 0 0 0 2 2 2 2 0 0 2 2 4 2 2 2 0 2 0 2 0 2 0 0
1 2 0 0 0 2 0 0 0 2 0 2 0 2 2 0 0 2 2 2 2 2 2 2 0 8
1 2 0 0 2 2 0 0 2 2 2 2 2 0 2 0 2 0 0 0 0 0 0 2 8 8
1 2 0 2 0 2 0 2 0 0 0 0 2 2 2 2 2 0 0 0 0 0 2 6 0 8
1 2 2 2 2 2 2 2 0 0 0 2 0 0 0 0 2 0 0 0 0 2 4 6 8 6
1 0 0 0 0 0 0 2 0 0 2 2 0 0 0 2 2 0 0 0 2 2 2 2 2 4
MATHEMATICA
t = Prime[Range[1000]]; r[1] = t; r[2] = Abs[Differences[t]];
r[n_] := r[n] = Abs[Differences[r[n - 1]]];
a[n_] := Select[Range[150], r[n][[#]] == 0 &, 1]
Join[{1, 1}, Flatten[Table[a[n], {n, 1, 120}]]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Nov 23 2022
STATUS
approved