A112381 - OEIS

A112381

Zero-free semiprimes.

4, 6, 9, 14, 15, 21, 22, 25, 26, 33, 34, 35, 38, 39, 46, 49, 51, 55, 57, 58, 62, 65, 69, 74, 77, 82, 85, 86, 87, 91, 93, 94, 95, 111, 115, 118, 119, 121, 122, 123, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 169, 177, 178, 183, 185, 187

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

OFFSET

1,1

COMMENTS

Intersection of A001358 and A052382. - Michel Marcus, Oct 09 2013

LINKS

Table of n, a(n) for n=1..59.

EXAMPLE

74 is in the sequence because it is a semiprime (2*37) and does not have 0 in digits. - Michel Marcus, Oct 14 2013

MATHEMATICA

SemiPrimeQ[n_Integer] := If[Abs[n] < 2, False, (2 == Plus @@ Transpose[FactorInteger[Abs[n]]][[2]])]; Select[Range[2, 200], SemiPrimeQ[#] && Min[IntegerDigits[#]] > 0 &] (* T. D. Noe, Oct 11 2013 *)

PROG

(PARI) lista(nn) = {vec = vector(nn, i, i); pp = select(i->(((bigomega(i) == 2) && vecmin(digits(i)))), vec); print(pp); } \\ Michel Marcus, Oct 09 2013

CROSSREFS

Sequence in context: A241451 A354965 A288379 * A182150 A108634 A135355

Adjacent sequences: A112378 A112379 A112380 * A112382 A112383 A112384

KEYWORD

base,nonn

AUTHOR

Zak Seidov, May 30 2006

EXTENSIONS

Data corrected by Michel Marcus, Oct 14 2013

STATUS

approved