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 A253380 Numbers k such that 17^k + 4 is prime. 0
 0, 2, 6, 18, 7238 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS No further terms up to 10000. No further terms up to 37200. - Michael S. Branicky, Mar 22 2023 LINKS Table of n, a(n) for n=1..5. EXAMPLE For k = 0: 17^0 + 4 = 5, which is prime, so 0 is a term of the sequence. For k = 2: 17^2 + 4 = 293, which is prime, so 2 is a term of the sequence. MATHEMATICA Select[Range@10^5, PrimeQ[17^# + 4] &] (* Michael De Vlieger, Jan 03 2015 *) PROG (PARI) for(n=0, 1e5, if(ispseudoprime(17^n+4), print1(n, ", "))) CROSSREFS Corresponding sequences for k^n+4: A058958 (k=3), A124621 (k=5), A096305(k=7), A217384 (k=9), A137236 (k=13), A247166 (k=15), A243397 (k=19). Sequence in context: A064535 A240643 A262971 * A128123 A227884 A186769 Adjacent sequences: A253377 A253378 A253379 * A253381 A253382 A253383 KEYWORD nonn,more AUTHOR Felix Fröhlich, Dec 31 2014 STATUS approved

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Last modified February 25 10:32 EST 2024. Contains 370321 sequences. (Running on oeis4.)