A175620 Triangle read by rows: T(n,k) = 2^(prime(n) - k - 1) mod n, 1 <= k <= n.

0, 0, 1, 2, 1, 2, 0, 0, 0, 0, 2, 1, 3, 4, 2, 2, 4, 2, 4, 2, 4, 1, 4, 2, 1, 4, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 8, 4, 2, 1, 5, 7, 8, 4, 2, 8, 4, 2, 6, 8, 4, 2, 6, 8, 4, 6, 3, 7, 9, 10, 5, 8, 4, 2, 1, 6, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 4, 2, 1, 7, 10, 5, 9, 11, 12, 6, 3, 8

Offset

1,4

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Example

Triangle begins:
  0;
  0, 1;
  2, 1, 2;
  0, 0, 0, 0;
  2, 1, 3, 4, 2;
  2, 4, 2, 4, 2, 4;

Maple

A175620 := proc(n, k) modp(2^(ithprime(n)-k-1) , n) ; end proc: # R. J. Mathar, Dec 14 2010

Mathematica

Flatten[Table[PowerMod[2, Prime[n]-k-1, n], {n, 20}, {k, n}]] (* Harvey P. Dale, Dec 10 2012 *)

Prog

(Magma)
[Modexp(2, NthPrime(n)-k-1, n): k in [1..n], n in [1..15]]; // G. C. Greubel, Apr 12 2024
(SageMath)
flatten([[pow(2, nth_prime(n)-k-1, n) for k in range(1, n+1)] for n in range(1, 16)]) # G. C. Greubel, Apr 12 2024

Crossrefs

Cf. A000079, A173655, A177226.

Sequence in context: A152439 A070965 A079548 * A319812 A079071 A322795

Adjacent sequences: A175617 A175618 A175619 * A175621 A175622 A175623

Keyword

nonn,tabl,changed

Author

Juri-Stepan Gerasimov, Dec 12 2010

Status

approved