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 A271184 Löschian numbers (A003136) of the form k^2+1. 1
 1, 37, 325, 577, 1297, 2917, 3601, 4357, 7057, 8101, 9217, 14401, 15877, 22501, 24337, 28225, 32401, 41617, 44101, 46657, 57601, 60517, 69697, 72901, 79525, 86437, 90001, 93637, 108901, 133957, 147457, 156817, 176401, 197137, 202501, 219025, 224677, 236197, 291601, 298117, 318097 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Intersection of A002522 and A003136. Corresponding values of k are 0, 6, 18, 24, 36, 54, 60, 66, 84, 90, 96, 120, 126, 150, 156, 168, 180, 204, 210, 216, 240, 246, 264, 270, 282, 294, 300, 306, ... LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 EXAMPLE 37 is a term because 37 = 6^2 + 1 = 4^2 + 4*3 + 3^2. MATHEMATICA Select[Range[10^6], And[IntegerQ@Sqrt[# - 1], Resolve[Exists[{x, y}, Reduce[# == x^2 + x y + y^2, {x, y}, Integers]]]] &] (* Michael De Vlieger, Apr 01 2016 *) PROG (PARI) is(n) = #bnfisintnorm(bnfinit(z^2+z+1), n); for(k=0, 2000, if(is(n=k^2+1), print1(n, ", "))); CROSSREFS Cf. A002522, A003136. Sequence in context: A114785 A061014 A130450 * A217117 A291859 A133554 Adjacent sequences:  A271181 A271182 A271183 * A271185 A271186 A271187 KEYWORD nonn AUTHOR Altug Alkan, Apr 01 2016 STATUS approved

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Last modified May 26 17:16 EDT 2022. Contains 354092 sequences. (Running on oeis4.)