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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A075234 Least k such that k^n is the smallest interprime which is an n-th power. 10
4, 2, 4, 3, 20, 2, 20, 12, 9, 9, 24, 2, 23, 26, 20, 66, 10, 3, 16, 3, 92, 13, 18, 48, 230, 129, 78, 181, 315, 33, 231, 19, 14, 152, 78, 39, 39, 4, 144, 9, 143, 55, 106, 25, 10, 91, 17, 7, 107, 91, 35, 44, 426, 81, 380, 97, 265, 237, 611, 1034, 122, 1072, 298, 1213, 18, 51 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Interprimes are in A024675, even interprimes are in A072568, odd interprimes are in A072569 n^2 as interprimes are in A075190, n^3 as interprimes are in A075191, n^4 as interprimes are in A075192, n^5 as interprimes are in A075228, n^6 as interprimes are in A075229, n^7 as interprimes are in A075230, n^8 as interprimes are in A075231, n^9 as interprimes are in A075232, n^10 as interprimes are in A075233.

LINKS

Moshe Levin, Table of n, a(n) for n = 1..100 (large primes well may be only pseudoprimes)

EXAMPLE

a(1)=4 because 4^1 = 4 is the smallest interprime of the form a^1, a(2)=2 because 2^2 = 4 is the smallest interprime of the form a^2, a(3)=4 because 4^3 = 64 is the smallest interprime of the form a^3, a(5)=20 because 20^5 = 3200000 is the smallest interprime of the form a^5. a(29)=315 because 315^29 =  2824919391960653953906106164519699385714864156233560852706432342529296875 is the smallest interprime of the form a^29.

MAPLE

s := 10: for n from 2 to 1000 do if prevprime(n^s)+nextprime(n^s)=2*n^s then print(n) else; fi; od;

MATHEMATICA

PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; a = {}; Do[k = 2; While[2k^n != PrevPrim[k^n] + NextPrim[k^n], k++ ]; a = Append[a, k], {n, 1, 67}]; a

CROSSREFS

Cf. A024675, A072568, A072569, A075190-A075192, A075228-A075234.

The first 10 terms in this sequence are the first terms in A024675, A075190-A075192, A075228-A075233.

Sequence in context: A038702 A085062 A053051 * A232715 A095382 A135282

Adjacent sequences:  A075231 A075232 A075233 * A075235 A075236 A075237

KEYWORD

nonn

AUTHOR

Zak Seidov, Sep 09 2002

EXTENSIONS

Edited and extended by Robert G. Wilson v, Sep 14 2002

Typos in EXAMPLE fixed by Moshe Levin, Feb 09 2012

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified March 24 21:58 EDT 2017. Contains 284001 sequences.