The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A177266 Triangle read by rows: R(n,k)=2^(semiprime(n)-semiprime(k)) mod semiprime(n). 0
 1, 4, 1, 5, 8, 1, 4, 6, 2, 1, 2, 4, 4, 2, 1, 8, 2, 4, 2, 2, 1, 11, 8, 1, 11, 2, 1, 1, 14, 20, 8, 4, 14, 18, 2, 1, 2, 13, 11, 18, 23, 24, 16, 8, 1, 10, 22, 6, 16, 14, 20, 6, 16, 2, 1, 17, 29, 16, 8, 17, 25, 4, 2, 25, 29, 1, 30, 16, 2, 18, 16, 8, 32, 16, 2, 18, 2, 1, 23, 32, 4, 2, 22 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE Triangle begins: 1, 4, 1, 5, 8, 1, 4, 6, 2, 1, 2, 4, 4, 2, 1, 8, 2, 4, 2, 2, 1, PROG (PARI) trg(nn) = {semip = select(n->bigomega(n) == 2, vector(nn, i, i)); for (n = 1, #semip, for (k = 1, n, print1(2^(semip[n] - semip[k]) % semip[n], ", "); ); print(); ); } \\ Michel Marcus, Sep 11 2013 CROSSREFS Cf. A000079, A001358, A173622, A174479, A176066, A181615. Sequence in context: A058662 A133866 A242131 * A272534 A332522 A173386 Adjacent sequences:  A177263 A177264 A177265 * A177267 A177268 A177269 KEYWORD nonn,tabl AUTHOR Juri-Stepan Gerasimov, Dec 10 2010 EXTENSIONS Corrected by D. S. McNeil, Dec 10 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 10 04:38 EDT 2020. Contains 336368 sequences. (Running on oeis4.)