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A091277 Numbers k such that the k-th prime is of the form m^2 + (m+1)^2. 5
3, 6, 13, 18, 30, 42, 65, 82, 112, 135, 170, 197, 212, 271, 284, 319, 353, 369, 445, 505, 612, 682, 933, 1069, 1193, 1226, 1286, 1510, 1609, 1676, 1711, 1789, 1900, 2161, 2241, 2285, 2363, 2450, 2667, 2712, 2924, 3247, 3644, 3894, 4000, 4100, 4367, 4647, 4922 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also, the k-th prime is of the form (m^2+1)/2.

LINKS

Jinyuan Wang, Table of n, a(n) for n = 1..1000 (terms 1..500 from Harvey P. Dale)

FORMULA

a(n)=k such that A000040(k)=A027862(n).

MATHEMATICA

Select[Range[5000], OddQ[Sqrt[2Prime[#]-1]]&] (* Harvey P. Dale, Jun 25 2018 *)

CROSSREFS

A027862 indexed by A000040.

Cf. A002731, A027861, A027862.

Sequence in context: A115283 A078382 A075651 * A136484 A263621 A137039

Adjacent sequences:  A091274 A091275 A091276 * A091278 A091279 A091280

KEYWORD

nonn,easy

AUTHOR

Ray Chandler, Jan 03 2004

EXTENSIONS

Offset changed to 1 by Jinyuan Wang, Aug 02 2021

STATUS

approved

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Last modified October 1 04:05 EDT 2022. Contains 357134 sequences. (Running on oeis4.)