cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-14 of 14 results.

A179916 Primes with eight embedded primes.

Original entry on oeis.org

12373, 12379, 12713, 13171, 15233, 17333, 17359, 17971, 19373, 19379, 21139, 21319, 22973, 23167, 23197, 23311, 23473, 23537, 23593, 23671, 23677, 23761, 23773, 23977, 24113, 24137, 24179, 24197, 24317, 24337, 24379, 24733, 25237
Offset: 1

Views

Author

Robert G. Wilson v, Aug 01 2010

Keywords

Comments

A079066(a(n)) = 8.

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndices)
    a179916 n = a179916_list !! (n-1)
    a179916_list = map (a000040 . (+ 1)) $ elemIndices 8 a079066_list
    -- Reinhard Zumkeller, Jul 19 2011
  • 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@ 2790, f@# == 9 &]

A179917 Primes with nine embedded primes.

Original entry on oeis.org

11317, 19739, 19973, 21317, 21379, 22397, 22937, 23117, 23173, 23371, 23971, 24373, 26317, 27197, 29173, 29537, 32719, 33739, 33797, 37397, 39719, 51137, 51973, 52313, 53173, 53479, 53719, 57173, 57193, 61379, 61979, 63179, 66173
Offset: 1

Views

Author

Robert G. Wilson v, Aug 01 2010

Keywords

Comments

A079066(a(n)) = 9.

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndices)
    a179917 n = a179917_list !! (n-1)
    a179917_list = map (a000040 . (+ 1)) $ elemIndices 9 a079066_list
    -- Reinhard Zumkeller, Jul 19 2011
  • 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@ 6610, f@# == 10 &]

A179918 Primes with ten embedded primes.

Original entry on oeis.org

23719, 31379, 52379, 111373, 111731, 111733, 112397, 113117, 113167, 113723, 113759, 113761, 115237, 117191, 117431, 121139, 122971, 123113, 123373, 123479, 123731, 124337, 126173, 126317, 127139, 127733, 127739, 127973, 129733, 131171
Offset: 1

Views

Author

Robert G. Wilson v, Aug 01 2010

Keywords

Comments

A079066(a(n)) = 10.

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndices)
    a179918 n = a179918_list !! (n-1)
    a179918_list = map (a000040 . (+ 1)) $ elemIndices 10 a079066_list
    -- Reinhard Zumkeller, Jul 19 2011
  • 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@ 12280, f@# == 11 &]

A179924 Primes with embedded primes.

Original entry on oeis.org

13, 17, 23, 29, 31, 37, 43, 47, 53, 59, 67, 71, 73, 79, 83, 97, 103, 107, 113, 127, 131, 137, 139, 151, 157, 163, 167, 173, 179, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337
Offset: 1

Views

Author

Robert G. Wilson v, Aug 01 2010

Keywords

Comments

A079066(a(n)) > 0. - Reinhard Zumkeller, Jul 19 2011
Is there a prime such that the previous prime is embedded in it? - Ivan N. Ianakiev, Nov 09 2023. Answer from Amiram Eldar: No. If prime(n) is embedded in prime(n+1) then prime(n+1) has at least one digit more than prime(n), so prime(n+1) > 2 * prime(n). But according to Bertrand's postulate, prime(n+1) < 2*prime(n).

Crossrefs

Programs

  • Haskell
    import Data.List (findIndices)
    a179924 n = a179924_list !! (n-1)
    a179924_list = map (a000040 . (+ 1)) $ findIndices (> 0) a079066_list
    -- Reinhard Zumkeller, Jul 19 2011
  • 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@ 68, f@# > 1 &]
Previous Showing 11-14 of 14 results.