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A094048 Let p(n) be the n-th prime congruent to 1 mod 4. Then a(n) = the least m for which m^2+1=p(n)*k^2 has a solution. 8
2, 18, 4, 70, 6, 32, 182, 29718, 1068, 500, 5604, 10, 8890182, 776, 1744, 113582, 4832118, 1118, 1111225770, 1764132, 14, 1710, 23156, 71011068, 16, 82, 8920484118, 1063532, 2482, 126862368, 352618 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A191860. [Reinhard Zumkeller, Jun 18 2011]

LINKS

Table of n, a(n) for n=1..31.

MATHEMATICA

f[n_] := Block[{y = 1}, While[ !IntegerQ[ Sqrt[n*y^2 - 1]], y++ ]; Sqrt[n*y^2 - 1]]; lst = {}; Do[p = Prime@ n; If[ Mod[p, 4] == 1, AppendTo[lst, f@p]; Print[{n, Prime@n, f@p}]], {n, 66}]; lst

PROG

(Haskell)

a094048 n = head [m | m <- map (a037213 . subtract 1 . (* a002144 n))

                               (tail a000290_list), m > 0]

-- Reinhard Zumkeller, Jun 13 2015

CROSSREFS

Cf. A002144, A094049 (associated k), A130226, A137351, A179073.

Cf. A000196, A037213, A000290.

Sequence in context: A077452 A113918 A253603 * A179073 A087665 A093481

Adjacent sequences:  A094045 A094046 A094047 * A094049 A094050 A094051

KEYWORD

nonn

AUTHOR

Matthijs Coster, Apr 29 2004

EXTENSIONS

Edited by Don Reble, Apr 30 2004

STATUS

approved

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Last modified October 18 01:39 EDT 2021. Contains 348065 sequences. (Running on oeis4.)