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A173662
Triangle read by rows: T(n,k) = semiprime(n) mod semiprime(k), 1 <= k <= n.
2
0, 2, 0, 1, 3, 0, 2, 4, 1, 0, 2, 2, 5, 4, 0, 3, 3, 6, 5, 1, 0, 1, 3, 3, 1, 7, 6, 0, 2, 4, 4, 2, 8, 7, 1, 0, 1, 1, 7, 5, 11, 10, 4, 3, 0, 2, 2, 8, 6, 12, 11, 5, 4, 1, 0, 1, 3, 6, 3, 5, 3, 12, 11, 8, 7, 0, 2, 4, 7, 4
OFFSET
1,2
COMMENTS
Row sums are 0, 2, 4, 7, 13, 18, 28, ...
EXAMPLE
Triangle begins:
0,
2,0;
1,3,0;
2,4,1,0;
2,2,5,4,0;
3,3,6,5,1,0;
1,3,3,1,7,6,0;
2,4,4,2,8,7,1,0;
MATHEMATICA
SemiprimeQ[n_Integer] := If[Abs[n]<2, False, (2==Plus@@Transpose[FactorInteger[Abs[n]]][[2]])]; sp = Select[Range[100], SemiprimeQ]; Flatten[Table[Mod[sp[[n]], sp[[Range[n]]]], {n, Length[sp]}]]
CROSSREFS
Sequence in context: A128097 A328096 A353778 * A263406 A257230 A357136
KEYWORD
nonn,tabl,easy
AUTHOR
EXTENSIONS
46th term corrected by D. S. McNeil, Nov 24 2010
STATUS
approved