login
A062066
a(1) = 2; a(n) is the smallest prime > a(n-1) such that a(n) + a(n-1) is a cube.
3
2, 727, 2017, 11807, 15193, 39679, 70913, 124199, 314777, 1090151, 1895833, 3017167, 4982833, 8841167, 10841833, 14570351, 17587081, 24557111, 26095889, 27061487, 32257513, 45051263, 46073737, 61776439, 72441289, 74756663, 82707337, 114430031, 157667761, 170841239
OFFSET
1,1
LINKS
Zak Seidov, Table of n, a(n) for n = 1..10000 (first 45 terms from Harry J. Smith)
EXAMPLE
The next term after 727 is 2017 as 727 + 2017 = 2744 = 14^3.
MATHEMATICA
a=2; s={a}; c=1; k=1; Do[Label[ne]; If[PrimeQ[b=k^3-a]&&b>a, a=b; c++; AppendTo[s, a]; If[c==10000, Break[]]]; k++; Goto[ne], {1}]; s (*Zak Seidov, Sep 28 2011*)
sp[n_]:=Module[{c=Floor[Surd[NextPrime[2n], 3]]+1}, While[!PrimeQ[ c^3- n], c++]; c^3-n]; NestList[sp, 2, 30] (* Harvey P. Dale, Dec 19 2015 *)
PROG
(PARI) iscube(x)= { f=factor(x)~; for(i=1, length(f), if (t=f[2, i]%3, return(0))); return(1); } { a=2; for (n=1, 45, a1=a; if (n>1, until (iscube(a + a1), a=nextprime(a + 1))); write("b062066.txt", n, " ", a) ) } \\ Harry J. Smith, Jul 31 2009
CROSSREFS
Cf. A062064.
Sequence in context: A156008 A103169 A082438 * A174368 A082621 A053600
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Jun 12 2001
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), Jun 21 2001
Further terms from Philip Sung (phil(AT)main.nu), Sep 11 2001
STATUS
approved