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 A306190 a(n) = p^2 - p - 1 where p = prime(n), the n-th prime. 2
 1, 5, 19, 41, 109, 155, 271, 341, 505, 811, 929, 1331, 1639, 1805, 2161, 2755, 3421, 3659, 4421, 4969, 5255, 6161, 6805, 7831, 9311, 10099, 10505, 11341, 11771, 12655, 16001, 17029, 18631, 19181, 22051, 22649, 24491, 26405, 27721, 29755, 31861, 32579, 36289 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Terms are divisible by 5 iff p is of the form 10*m + 3 (A030431). LINKS Robert Israel, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A036689(n) - 1. a(n) = A036690(n) - A072055(n). a(n) = A060800(n) - A089241(n). EXAMPLE a(3) = 19 because 5^2 - 5 - 1 = 19. MAPLE map(p -> p^2-p-1, [seq(ithprime(i), i=1..100)]); # Robert Israel, Mar 11 2019 MATHEMATICA Table[Prime[n]^2-Prime[n]-1, {n, 1, 100}] (* Jinyuan Wang, Feb 02 2019 *) PROG (PARI) a(n) = {p=prime(n); p^2-p-1; } \\ Jinyuan Wang, Feb 02 2019 CROSSREFS Supersequence of A091568. Subsequence of A028387 or A165900. Cf. A000040, A030431, A036689, A036690, A060800, A072055, A089241. A039914 is an essentially identical sequence. Sequence in context: A140761 A100572 A119534 * A033622 A091568 A147307 Adjacent sequences:  A306187 A306188 A306189 * A306191 A306192 A306193 KEYWORD nonn AUTHOR Kritsada Moomuang, Jan 28 2019 STATUS approved

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Last modified August 23 13:58 EDT 2019. Contains 326229 sequences. (Running on oeis4.)