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A181615
Triangle read by rows: T(n,k) = 2^(n-1) mod semiprime(k).
2
1, 2, 2, 0, 4, 4, 0, 2, 8, 8, 0, 4, 7, 6, 2, 0, 2, 5, 2, 4, 2, 0, 4, 1, 4, 8, 4, 1, 0, 2, 2, 8, 2, 8, 2, 18, 0, 4, 4, 6, 4, 1, 4, 14, 6, 0, 2, 8, 2, 8, 2, 8, 6, 12, 18, 0, 4, 7, 4, 2, 4, 16, 12, 24, 10, 1, 0, 2, 5, 8, 4, 8, 11, 2, 23, 20, 2, 8, 0, 4, 1, 6, 8, 1, 1, 4, 21, 14, 4
OFFSET
1,2
EXAMPLE
Triangle begins:
1;
2, 2;
0, 4, 4;
0, 2, 8, 8;
0, 4, 7, 6, 2;
...
MATHEMATICA
Table[PowerMod[2, n-1, #[[;; n]]], {n, Length[#]}] & [Select[Range[50], PrimeOmega[#] == 2 &]] (* Paolo Xausa, Jun 29 2024 *)
PROG
(PARI) trg(nn) = {semip = select(n->bigomega(n) == 2, vector(nn, i, i)); for (n = 1, #semip, for (k = 1, n, print1(2^(n-1) % semip[k], ", "); ); print(); ); } \\ Michel Marcus, Sep 11 2013
CROSSREFS
Sequence in context: A276275 A128585 A217840 * A141333 A262967 A168090
KEYWORD
nonn,tabl
AUTHOR
EXTENSIONS
Corrected by T. D. Noe, Dec 02 2010
STATUS
approved