A242276 Irregular array of factors of n-th Poulet number read by rows, where row n corresponds to A001567(n).

11, 31, 3, 11, 17, 3, 5, 43, 5, 13, 17, 19, 73, 7, 13, 19, 3, 5, 127, 23, 89, 5, 17, 29, 37, 73, 7, 13, 31, 29, 113, 37, 109, 17, 257, 3, 31, 47, 31, 151, 43, 127, 7, 23, 41, 73, 109, 53, 157, 3, 11, 257, 7, 19, 67, 31, 331, 5, 29, 73, 5, 7, 17, 19, 3, 17, 251, 7, 13, 151, 59, 233, 11, 31, 41, 43, 337, 23, 683, 7, 31, 73, 5, 13

Offset

1,1

Links

Felix Fröhlich, Table of n, a(n) for n = 1..2165 (all terms up to 10^7)

Example

The first three Poulet numbers (2-pseudoprimes) are 341 = 11*31, 561 = 3*11*17, and 645 = 3*5*43, so the sequence begins:
11, 31;
3, 11, 17;
3, 5, 43;
etc.

Prog

(PARI) forcomposite(n=1, 1e4, if(Mod(2, n)^(n-1)==1, f=factor(n)[, 1]; for(i=1, #f, print1(f[i], ", "))))

Crossrefs

Cf. A001567, A007011, A084653, A084654, A084655.

Sequence in context: A002755 A346852 A157827 * A196374 A112260 A196114

Adjacent sequences: A242273 A242274 A242275 * A242277 A242278 A242279

Keyword

nonn,tabf

Author

Felix Fröhlich, Aug 16 2014

Status

approved