A119382 Indices j of prime numbers p(j) such that (p(j-1) + p(j+2)) / p(j) = 2.

12, 19, 59, 92, 112, 115, 140, 211, 233, 253, 261, 268, 276, 285, 291, 294, 301, 322, 352, 358, 369, 389, 407, 417, 473, 500, 542, 598, 612, 624, 714, 718, 723, 742, 819, 933, 939, 994, 998, 1016, 1098, 1119, 1263, 1299, 1312, 1400, 1414, 1418, 1422, 1449

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..3000

Example

a(1)=12 because the 11th prime 31 plus the 14th prime 43 divided by the 12th prime 37 equals 2.

Mathematica

Select[Range[2, 1500], (Prime[ # - 1] + Prime[ # + 2])/(Prime[ # ]) == 2 &] (* Stefan Steinerberger, Jul 26 2006 *)
Module[{c}, Off[Part::partd]; c=Flatten[Position[Partition[Prime[ Range[ 1500]], 4, 1], _?((#[[1]]+#[[4]])/#[[2]]==2&)]]+1; On[Part::partd]; c] (* Harvey P. Dale, Jan 01 2013 *)

Crossrefs

Sequence in context: A136770 A155574 A272100 * A166671 A357211 A331258

Adjacent sequences: A119379 A119380 A119381 * A119383 A119384 A119385

Keyword

nonn

Author

Axel Harvey, Jul 25 2006

Extensions

More terms from Stefan Steinerberger, Jul 26 2006

Status

approved