A071217 Numbers k such that the largest prime factor of the sum of successive primes p(k) + p(k+1) is greater than k.

1, 9, 11, 12, 19, 23, 24, 29, 31, 32, 51, 54, 58, 63, 67, 71, 75, 76, 77, 84, 86, 87, 93, 95, 97, 103, 108, 110, 124, 128, 136, 151, 158, 159, 164, 169, 188, 191, 192, 200, 202, 205, 208, 210, 211, 216, 227, 232, 241, 243, 245, 246, 247, 252, 265, 273, 278, 282

Offset

1,2

Links

Table of n, a(n) for n=1..58.

Formula

A071216(k) > k.

Example

p(9) + p(10) = 23 + 29 = 52 = 2*2*13 and 13 > 10, so index 9 is here; it is the 2nd term.

Mathematica

pf[x_] := Part[Reverse[Flatten[FactorInteger[x]]], 2] Do[s=pf[Prime[n+1]+Prime[n]]; If[Greater[s, n], Print[n]], {n, 1, 1000}]

Crossrefs

Cf. A001043, A006530, A071216.

Sequence in context: A031078 A216292 A250295 * A064930 A158607 A070699

Adjacent sequences: A071214 A071215 A071216 * A071218 A071219 A071220

Keyword

nonn

Author

Labos Elemer, May 17 2002

Status

approved