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

Author

Juri-Stepan Gerasimov, Dec 12 2010

Keywords

• nonn
• tabl

Examples

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

Links

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

Crossrefs

Cf. A000079, A173655, A177226.

Programs

Magma

[Modexp(2,NthPrime(n)-k-1,n): k in [1..n], n in [1..15]]; // G. C. Greubel, Apr 12 2024

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 *)

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