A132746 Numbers k such that prime(k) + prime(k+1) is a perfect power.

2, 7, 15, 18, 20, 28, 61, 152, 190, 293, 377, 492, 558, 564, 789, 919, 942, 1332, 1768, 2343, 2429, 2693, 2952, 3136, 3720, 3928, 4837, 5421, 5722, 6870, 7347, 8126, 8193, 9465, 9857, 9927, 10410, 10483, 10653, 12685, 13005, 13763, 13955, 16033, 16342

Offset

1,1

Comments

First terms absent in A064397: 2, 18, 28, 564, 1332, 3928, 12415, 13005, 16886.

Links

Table of n, a(n) for n=1..45.

Example

2 is a term because prime(2) + prime(3) = 3 + 5 = 8 = 2^3 (perfect power);
7 is a term because prime(7) + prime(8) = 17 + 19 = 36 = 6^2 (perfect power);
39867 is a term because prime(39867) + prime(39868) = 478241 + 478243 = 956484 = 978^2 (perfect power).

Prog

(PARI) s=[]; for(n=1, 41530, a=prime(n)+prime(n+1); if(ispower(a), s=concat(s, n))); s

Crossrefs

Cf. A064397 (numbers k such that prime(k) + prime(k+1) is a square).

Sequence in context: A088824 A034903 A070898 * A252475 A350043 A167543

Adjacent sequences: A132743 A132744 A132745 * A132747 A132748 A132749

Keyword

nonn

Author

Zak Seidov, Nov 17 2007

Status

approved