A248594 Semiprimes whose next four consecutive integers have exactly three, four, five, and six prime factors, respectively (allowing multiplicity of factors).

153221, 196621, 222422, 230261, 288437, 307373, 340421, 400082, 657302, 660713, 706073, 723461, 777773, 838562, 843521, 954581, 961621, 988601, 1009985, 1031846, 1034933, 1190822, 1215821, 1246802, 1384621, 1409873, 1612321, 1723082, 1737122, 1886441

Offset

1,1

Comments

This sequence is related to A113150; for instance, a(14) = 838562 = A113150(1) + 1, since 838561 is prime. - Michel Marcus, Oct 23 2014

Links

Table of n, a(n) for n=1..30.

Example

a(1)=153221 because 153221 is a product of 2 primes (17*9013) and
153222 is a product of 3 primes (2 * 3 * 25537) and
153223 is a product of 4 primes (7 * 7 * 53 * 59) and
153224 is a product of 5 primes (2 * 2 * 2 * 107 * 179) and
153225 is a product of 6 primes (3 * 3 * 3 * 5 * 5 * 227).

Prog

(PARI) isok(n) = bigomega(n)==2 && bigomega(n+1)==3 && bigomega(n+2)==4 && bigomega(n+3)==5 && bigomega(n+4)==6; \\ Michel Marcus, Oct 23 2014

Crossrefs

Cf. A001358, A113150.

Sequence in context: A233947 A172732 A172789 * A339528 A234553 A073086

Adjacent sequences: A248591 A248592 A248593 * A248595 A248596 A248597

Keyword

nonn,easy

Author

Gil Broussard, Oct 09 2014

Status

approved