login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

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 | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 9 16:42 EST 2019. Contains 329879 sequences. (Running on oeis4.)