This site is supported by donations to The OEIS Foundation.

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A179910 Primes with two embedded primes. 2
 23, 37, 53, 73, 127, 139, 157, 167, 193, 211, 227, 229, 241, 251, 263, 277, 307, 331, 383, 389, 419, 433, 439, 443, 457, 467, 503, 521, 541, 557, 563, 577, 587, 599, 619, 631, 643, 647, 659, 677, 683, 727, 751, 757, 761, 827, 829, 839, 857, 859, 883, 929 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS It appears that p having n embedded primes means that the set of prime integers generated by contiguous proper substrings of p has size n. A079066(a(n)) = 2. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..1000 MATHEMATICA f[n_] := Block[ {id = IntegerDigits@n}, len = Length@ id - 1; Count[ PrimeQ@ Union[ FromDigits@# & /@ Flatten[ Table[ Partition[ id, k, 1], {k, len}], 1]], True] + 1]; Select[ Prime@ Range@ 160, f@# == 3 &] Select[ Prime@ Range@ 160, Function[ n, Length@ Select[ Union[ FromDigits /@ (Flatten[ Table[ Partition[#, k, 1], {k, Length@ # - 1}], 1] &)@ IntegerDigits@ n], PrimeQ]]@ # == 2 &] (* Michael Somos, Jan 13 2011 *) PROG (Haskell) import Data.List (elemIndices) a179910 n = a179910_list !! (n-1) a179910_list = map (a000040 . (+ 1)) \$ elemIndices 2 a079066_list -- Reinhard Zumkeller, Jul 19 2011 CROSSREFS Cf. A039996, A079397, A033274, A034844, A092621, A179909 - A179919, A033274. Sequence in context: A190731 A092622 A129351 * A124888 A141521 A080906 Adjacent sequences:  A179907 A179908 A179909 * A179911 A179912 A179913 KEYWORD base,nonn AUTHOR Robert G. Wilson v, Aug 01 2010 STATUS approved

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

Content is available under The OEIS End-User License Agreement .