login
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
OFFSET
1,1
COMMENTS
Subsequence of A191860. [Reinhard Zumkeller, Jun 18 2011]
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.
Sequence in context: A353309 A113918 A253603 * A179073 A087665 A093481
KEYWORD
nonn
AUTHOR
Matthijs Coster, Apr 29 2004
EXTENSIONS
Edited by Don Reble, Apr 30 2004
STATUS
approved