OFFSET
1,1
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Donovan Johnson)
FORMULA
EXAMPLE
a(2) = 216: prime(28) + prime(29) = 107 + 109 = 216 = 6^3.
MAPLE
KD: = proc() local a, b, c; a: = ithprime(n) + ithprime(n+1); b:= evalf(a^(1/3)); if b=floor(b) then RETURN(a): fi; end: seq(KD(), n=1..1000000);
MATHEMATICA
Select[Total/@Partition[Prime[Range[155*10^5]], 2, 1], IntegerQ[Surd[#, 3]]&] (* or *) stcpQ[n_]:=Module[{p1=NextPrime[Floor[n/2], -1], p2=NextPrime[Ceiling[n/2]]}, n==p1+p2]; Select[Range[850]^3, stcpQ] (* The second program is much more efficient than the first. *) (* Harvey P. Dale, May 15 2022 *)
PROG
(PARI) n=0; forstep(j=2, 55778, 2, c=j^3; c2=c/2; if(precprime(c2)+nextprime(c2)==c, n++; write("b226524.txt", n " " c))) /* Donovan Johnson, Sep 02 2013 */
(Python)
from itertools import count, islice
from sympy import nextprime, prevprime
def agen(): yield from (c for c in (k**3 for k in count(2, step=2)) if prevprime(c//2+1) + nextprime(c//2-1) == c)
print(list(islice(agen(), 27))) # Michael S. Branicky, May 24 2022
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
K. D. Bajpai, Aug 31 2013
EXTENSIONS
Edited by M. F. Hasler, Jan 03 2020
STATUS
approved