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A065988 a(n) is the largest prime p < n such that n mod p is a perfect square; a(n) = 0 if no such prime exists. 1
0, 0, 2, 3, 2, 5, 3, 7, 5, 5, 7, 11, 3, 13, 11, 5, 13, 17, 5, 19, 17, 13, 19, 23, 7, 17, 23, 19, 7, 29, 11, 31, 29, 17, 31, 7, 11, 37, 23, 31, 37, 41, 17, 43, 41, 37, 43, 47, 7, 41, 47, 43, 37, 53, 23, 47, 53, 29, 43, 59, 19, 61, 59, 11, 61, 41, 29, 67, 53, 61, 67, 71, 37, 73, 71 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

PROG

(PARI) { for (n=1, 1000, p=precprime(n - 1);; while (p > 0 && !issquare(n%p), p=precprime(p - 1)); write("b065988.txt", n, " ", p) ) } \\ Harry J. Smith, Nov 05 2009

CROSSREFS

Sequence in context: A073890 A079311 A060474 * A075105 A265675 A094020

Adjacent sequences:  A065985 A065986 A065987 * A065989 A065990 A065991

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Dec 10 2001

STATUS

approved

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Last modified May 25 15:20 EDT 2019. Contains 323571 sequences. (Running on oeis4.)