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A145297 Smallest k such that k^2+1 is divisible by A002144(n)^4. 6
182, 239, 27493, 34522, 800982, 1251967, 623098, 6304056, 6459524, 20099637, 22709274, 35764191, 40317977, 54397650, 166206108, 187800003, 165728858, 152475014, 282599844, 312923750, 154613663, 485200742, 912190662, 548850444 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..24.

EXAMPLE

a(1) = 182 since A002144(1) = 5, 182^2+1 = 33125 = 5^4*53 and for no k < 182 does 5^4 divide k^2+1.

PROG

(PARI) {e=4; forprime(p=2, 250, if(p%4==1, q=p^e; m=q; while(!ispower(m-1, 2, &n), m=m+q); print1(n, ", ")))}

CROSSREFS

Cf. A002144 (primes of form 4n+1), A002313 (-1 is a square mod p), A059321, A145296, A145298, A145299.

Sequence in context: A054985 A124185 A218563 * A056091 A272361 A158553

Adjacent sequences:  A145294 A145295 A145296 * A145298 A145299 A145300

KEYWORD

nonn

AUTHOR

Klaus Brockhaus, Oct 11 2008

STATUS

approved

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Last modified June 15 22:19 EDT 2019. Contains 324145 sequences. (Running on oeis4.)