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A290098 Characteristic function for A003658 (fundamental discriminants of real quadratic fields). 3
1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

MATHEMATICA

Block[{nn = 105, t}, t = ConstantArray[0, nn]; ReplacePart[t, Map[# -> 1 &, Select[Range@ nn, NumberFieldDiscriminant@ Sqrt@ # == # &]]]] (* Michael De Vlieger, Aug 23 2017 *)

PROG

(PARI) A290098(n) = isfundamental(n);

CROSSREFS

Cf. A003658, A086669.

Sequence in context: A014017 A121262 A181923 * A102243 A173859 A202108

Adjacent sequences:  A290095 A290096 A290097 * A290099 A290100 A290101

KEYWORD

nonn

AUTHOR

Antti Karttunen, Aug 22 2017

STATUS

approved

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Last modified April 9 07:30 EDT 2020. Contains 333344 sequences. (Running on oeis4.)