A075192 - OEIS

A075192

Numbers k such that k^4 is an interprime = average of two successive primes.

3, 5, 8, 21, 55, 66, 87, 99, 104, 105, 110, 120, 129, 135, 141, 144, 152, 168, 172, 186, 187, 192, 211, 222, 243, 279, 283, 295, 297, 321, 342, 385, 395, 398, 408, 425, 426, 460, 520, 541, 559, 597, 626, 627, 638, 642, 657, 666, 673, 680, 713, 755, 759, 765

(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^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, a(n) such that a(n)^n = smallest interprime (of the form a^n) are in A075234.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

3 belongs to this sequence because 3^4 = 81 is the average of two successive primes 79 and 83.

MAPLE

s := 4: for n from 2 to 1000 do if prevprime(n^s)+nextprime(n^s)=2*n^s then print(n) else; fi; od;

MATHEMATICA

intprQ[n_]:=Module[{c=n^4}, c==Mean[{NextPrime[c], NextPrime[c, -1]}]]; Select[Range[800], intprQ] (* Harvey P. Dale, Dec 01 2013 *)

CROSSREFS

Cf. A024675, A072568, A072569, A075190, A075191.

Cf. A075228, A075229, A075230, A075231, A075232, A075233, A075234.

Sequence in context: A002366 A377254 A141615 * A361089 A101984 A292492