A120456 Antidiagonal triangular version of the modulo 15 prime multiplication table past n=3.

1, 2, 2, 4, 4, 4, 7, 8, 8, 7, 8, 14, 1, 14, 8, 11, 1, 13, 13, 1, 11, 13, 7, 2, 4, 2, 7, 13, 14, 11, 14, 11, 11, 14, 11, 14

Offset

0,2

Comments

This modulo 15 of prime digit endings is important because it gives even odd prime types that appear in pairs: {1,4},{2,13},{7,8},{11,14}

Links

Table of n, a(n) for n=0..35.

Formula

b[n]={1, 2, 4, 7, 8, 11, 13, 14} T[n,m]=Mod[b[n]*b[m],15] a(n) = T[n,m]: antidiagonal form

Example

Array looks like:
1, 2, 4, 7, 8, 11, 13, 14
2, 4, 8, 14, 1, 7, 11, 13
4, 8, 1, 13, 2, 14, 7, 11
7, 14, 13, 4, 11, 2, 1, 8
8, 1, 2, 11, 4, 13, 14, 7
11, 7, 14, 2, 13, 1, 8, 4
13, 11, 7, 1, 14, 8, 4, 2
14, 13, 11, 8, 7, 4, 2, 1

Mathematica

Table[Mod[Prime[n], 15], {n, 1, 50}] a = {1, 2, 4, 7, 8, 11, 13, 14} b = Table[Mod[a[[n]]*a[[m]], 15], {n, 1, 8}, {m, 1, 8}] c = Table[Table[b[[n, l - n]], {n, 1, l - 1}], {l, 1, Dimensions[b][[1]] + 1}] Flatten[c]

Crossrefs

Sequence in context: A317419 A364843 A372678 * A367039 A115383 A219156

Adjacent sequences: A120453 A120454 A120455 * A120457 A120458 A120459

Keyword

nonn,tabf,fini

Author

Roger L. Bagula, Jun 23 2006

Status

approved