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 A318527 Numbers k such that -3 is a quadratic residue (not necessarily coprime) modulo k, k + 1, k + 2 and k + 3. 3
 1, 721, 4681, 6121, 6481, 7201, 7561, 9001, 11161, 14401, 16921, 18361, 19441, 20521, 24481, 24841, 27361, 29881, 32761, 36721, 39241, 39601, 42121, 42841, 43201, 47161, 47521, 48241, 49681, 51121, 52201, 53641, 60481, 61561, 62641, 63361, 64441, 65521, 65881, 68041, 73441, 73801, 74521, 74881, 75961, 76321, 78481, 82441, 82801, 84241, 88201, 91081, 94681 (list; graph; refs; listen; history; text; internal format)