The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A335346 Lesser of two consecutive semiprimes whose sum and difference are also semiprimes. 1
 51, 65, 87, 111, 129, 146, 209, 249, 278, 291, 305, 335, 377, 407, 447, 485, 489, 497, 629, 681, 699, 749, 767, 785, 917, 939, 951, 989, 1007, 1018, 1037, 1115, 1177, 1191, 1257, 1397, 1457, 1469, 1497, 1509, 1546, 1565, 1594, 1707, 1731, 1757, 1799, 1945, 1977 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Intersection of A272306 and A272307. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE 51 = A272306(8) = A272307(3), 65 = A272306(10) = A272307(5). MAPLE b:= 4: Res:= NULL: count:= 0: while count < 100 do a:= b; for k from b+1 do if numtheory:-bigomega(k) = 2 then b:= k; break fi od: if numtheory:-bigomega(b-a) = 2 and numtheory:-bigomega(b+a) = 2 then count:= count+1; Res:= Res, a; fi od: Res; # Robert Israel, Nov 10 2022 PROG (PARI) psp=4; for(k=6, 2000, if(bigomega(k)==2, if(bigomega(k-psp)==2, if(bigomega(k+psp)==2, print1(psp, ", "))); psp=k)) \\ Hugo Pfoertner, Jun 03 2020 CROSSREFS Cf. A001358, A272306, A272307, A272308, A272309. Sequence in context: A206525 A216055 A034819 * A118147 A015863 A232105 Adjacent sequences: A335343 A335344 A335345 * A335347 A335348 A335349 KEYWORD nonn AUTHOR Zak Seidov, Jun 02 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 16 10:51 EDT 2024. Contains 374345 sequences. (Running on oeis4.)