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A145298 Smallest k such that k^2+1 is divisible by A002144(n)^5. 6
1068, 143044, 390112, 7745569, 6423465, 46464143, 23048345, 144762466, 404034898, 2153335831, 331407850, 1108900220, 2581164875, 760839155, 10734466938, 6595297216, 773302059, 61063137802, 31915893786, 112699451831 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..20.

EXAMPLE

a(4) = 7745569 since A002144(4) = 29, 7745569^2+1 = 59993839133762 = 2*29^5*97*15077 and for no k < 7745569 does 29^5 divide k^2+1.

PROG

(PARI) {e=5; forprime(p=2, 200, 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, A145297, A145299.

Sequence in context: A218564 A234880 A218565 * A145299 A289702 A095673

Adjacent sequences:  A145295 A145296 A145297 * A145299 A145300 A145301

KEYWORD

nonn

AUTHOR

Klaus Brockhaus, Oct 14 2008

STATUS

approved

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Last modified April 20 22:22 EDT 2019. Contains 322310 sequences. (Running on oeis4.)