A242756 Semiprimes having only the curved digits.

6, 9, 22, 25, 26, 33, 35, 38, 39, 55, 58, 62, 65, 69, 82, 85, 86, 93, 95, 202, 203, 205, 206, 209, 226, 235, 253, 259, 262, 265, 289, 295, 298, 299, 302, 303, 305, 309, 323, 326, 329, 335, 339, 355, 358, 362, 365, 382, 386, 393, 395, 398, 502, 505, 526, 529, 533

Offset: 1

Author

K. D. Bajpai, May 22 2014

Keywords

• nonn
• base

Comments

A curved-digit semiprime has only the curved digits, i.e., 0, 2, 3, 5, 6, 8 or 9.

Examples

			358 = 2 * 179 is semiprime having only the curved digits 3, 5 and 8. Hence appears in the sequence.
689 = 13 * 53 is semiprime having only the curved digits 6, 8 and 9. Hence appears in the sequence.
		

Links

• K. D. Bajpai, Table of n, a(n) for n = 1..3484

Crossrefs

Cf. A028374, A001358, A034470.

Programs

Mathematica

A242756 = {}; Do[a = PrimeOmega[n];If[a == 2 && Intersection[IntegerDigits[n], {1, 4, 7}] == {}, AppendTo[A242756, n]], {n, 1000}]; A242756

PARI

s=[]; for(n=1, 600, if(bigomega(n)==2 && setintersect(vecsort(digits(n), , 8), [1,4,7])==[], s=concat(s, n))); s \\ Colin Barker, Jun 03 2014