A153661 Triangle read by rows: R(n,k) = 2^(composite(n)-composite(k)) mod composite(n), 1<=k<=n.

1, 4, 1, 0, 4, 1, 5, 8, 2, 1, 4, 6, 4, 2, 1, 4, 4, 4, 8, 4, 1, 2, 4, 8, 4, 2, 4, 1, 8, 2, 8, 4, 2, 8, 2, 1, 0, 0, 0, 0, 0, 0, 4, 2, 1, 4, 10, 16, 8, 4, 10, 16, 8, 4, 1, 16, 4, 16, 8, 4, 16, 4, 12, 16, 4, 1, 11, 8, 2, 1, 11, 8, 2, 1, 11, 8, 2, 1, 14, 20, 16, 8, 4, 12, 14, 18, 20, 16, 4, 2, 1, 16, 16, 16, 8, 16, 16, 16, 8, 16, 16, 16, 8, 4, 1

Offset: 1

Author

Juri-Stepan Gerasimov, Dec 12 2010

Keywords

• nonn
• tabl
• easy
• less

Examples

			Triangle begins:
1,
4, 1,
0, 4, 1,
5, 8, 2, 1,
4, 6, 4, 2, 1,
4, 4, 4, 8, 4, 1,
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1035

Crossrefs

Cf. A000079, A002808, A175156.

Programs

Maple

A153661 := proc(n,k) modp(2^(A002808(n)-A002808(k)),A002808(n)) ;end proc: # R. J. Mathar, Dec 15 2010

Mathematica

Composite[m_] := FixedPoint[m + PrimePi[#] + 1 &, m + PrimePi[m] + 1]; a[n_, k_] := Mod[2^(Composite[n] - Composite[k]), Composite[n]]; Table[a[n, k], {n, 1, 15}, {k, 1, n}]; Flatten[%] (* G. C. Greubel, Aug 24 2016 *)

Extensions

Terms corrected by R. J. Mathar, Dec 15 2010