A091384 - OEIS

A091384

Members of the difference sequence (A091381) of the sequence of largest quadratic "mixed" residues modulo the primes (A091380) where the latter is non-monotonic.

0, -1, -5, -1, -3, 0, 0, -8, 0, -1, 0, -7, -2, -6, -1, 0, 0, -5, -6, 0, 0, -7, -2, 0, -2, -3, -1, 0, -1, -5, -5, -7, -2, -11, 0, -1, 0, 0, -1, -2, -10, 0, 0, -6, -3, -1, -5, -5, -6, -5, 0, -1, -5, -7, -2, -5, -1, -5, 0, -2, -2, -7, 0, -7, -9, -4, -4, -8, -5, -13, 0, -4, -4, -7, -17, 0, -3, 0, -5, -1, -3, 0, -17, 0, -7, -6, -1, -2, -3, -3, 0

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OFFSET

1,3

COMMENTS

The negative values are either primes or composites (Cf. A088200).

LINKS

Table of n, a(n) for n=1..91.

Ferenc Adorjan, The sequence of largest quadratic residues modulo the primes

PROG

(PARI) {/* The difference sequence values where the sequence of the largest "mixed" QR modulo the primes is non-monotonic */ lqxr_nm_d(to)=local(v=[], k, r, q, p, e=1, n=0, i=1); while(n<to, i+=1; p=prime(i); k=p-1; r=p%4-2; while(kronecker(k, p)<>r, k-=1); if(k-e<=0, v=concat(v, k-e); n+=1); e=k); print(i); print(v) }

CROSSREFS

Cf. A091380, A091381, A091382, A091383, A091385, A088190, A088196, A088200.

Sequence in context: A165449 A019114 A201526 * A011305 A348317 A254378

Adjacent sequences: A091381 A091382 A091383 * A091385 A091386 A091387

KEYWORD

easy,sign

AUTHOR

Ferenc Adorjan (fadorjan(AT)freemail.hu)

STATUS

approved