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A025027 Least non-residue mod n is 19. 0
5711, 9239, 10391, 10799, 11422, 14951, 18478, 20782, 21598, 29902, 33049, 34319, 36599, 37489, 40031, 42719, 44641, 49009, 49921, 51769, 53089, 55441, 57119, 59929, 61151, 61871, 63361, 66098, 67369, 67679, 68638, 69001, 71569, 73198, 74978, 75479 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..36.

PROG

(PARI) residue(n, m)=local(r); r=0; for(i=1, floor(m/2), if(i^2%m==n, r=1)); r

isA025027(n)=local(a); a=1; forprime(p=2, 17, a=a && residue(p, n)); a=a && !residue(19, n); a \\ Michael B. Porter, Apr 30 2010

(PARI) is(n)=forprime(p=2, 19, if(!issquare(Mod(p, n)), return(p==19))); 0 \\ Charles R Greathouse IV, Jan 24 2020

CROSSREFS

Sequence in context: A235207 A252342 A237743 * A030469 A244163 A253423

Adjacent sequences:  A025024 A025025 A025026 * A025028 A025029 A025030

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 28 21:37 EDT 2020. Contains 334690 sequences. (Running on oeis4.)