A065729 - OEIS

A065729

n-th partition number (A000041(n)) is a semiprime.

7, 8, 12, 23, 65, 67, 76, 81, 87, 90, 92, 93, 95, 121, 123, 143, 146, 161, 181, 203, 218, 220, 235, 241, 251, 252, 287, 321, 330, 388, 406, 423, 437, 438, 443, 455, 456, 507, 555, 594, 603, 626, 646, 661, 665, 672, 685, 707, 708, 715, 720, 755, 808, 837, 856

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..100

Hisanori Mishima, Factorization results

Eric Weisstein's World of Mathematics, Semiprime.

EXAMPLE

The 808th partition number 8151756509675604512522473567 = 5963320232189 * 1366982853893003.

PROG

(PARI) { n=0; for (m=1, 10^9, p=numbpart(m); if (bigomega(p) == 2, write("b065729.txt", n++, " ", m); if (n==100, return)) ) } \\ Harry J. Smith, Oct 28 2009

CROSSREFS

Intersection of A001358 and A000041.

Cf. A049575, A065728.

Sequence in context: A050901 A105832 A059177 * A156605 A343298 A061905

Adjacent sequences: A065726 A065727 A065728 * A065730 A065731 A065732

KEYWORD

nonn

AUTHOR

Patrick De Geest, Nov 18 2001

EXTENSIONS

Offset changed from 0 to 1 by Harry J. Smith, Oct 28 2009

Missing a(38) = 507 added by Harry J. Smith, Oct 28 2009

STATUS

approved