A175486 Composite numbers of form 8n+5 with all prime factors of form 8m+5.

125, 325, 725, 845, 925, 1325, 1525, 1885, 2197, 2405, 2525, 2725, 3125, 3445, 3725, 3925, 3965, 4205, 4325, 4525, 4901, 4925, 5365, 5725, 6253, 6565, 6725, 6845, 6925, 7085, 7325, 7685, 7925, 8125, 8725, 8845, 8957, 9325, 9685, 9725, 9805, 9925, 10205

Offset

1,1

Comments

There are no squares and no semiprimes in the sequence.

Links

Table of n, a(n) for n=1..43.

Example

125=5^3, 325=5^2*13, 725=5^2*29.

Mathematica

Do[nn=8n+5; If[ !PrimeQ[nn]&&{5}==Union[Mod[(fi=First/@FactorInteger[nn]), 8]], Print[nn]], {n, 2*10^3}]

Crossrefs

Cf. A004770 Numbers of form 8n+5, A175461 Semiprimes of form 8n+5, A007521 Primes of form 8n+5.

Sequence in context: A253226 A223182 A256362 * A250579 A161855 A353502

Adjacent sequences: A175483 A175484 A175485 * A175487 A175488 A175489

Keyword

nonn

Author

Zak Seidov, May 27 2010

Status

approved