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 A198244 Primes of the form k^10 + k^9 + k^8 + k^7 + k^6 + k^5 + k^4 + k^3 + k^2 + k + 1 where k is nonprime. 2
 11, 10778947368421, 17513875027111, 610851724137931, 614910264406779661, 22390512687494871811, 22793803793211153712637, 79905927161140977116221, 184251916941751188170917, 319465039747605973452001, 1311848376806967295019263, 1918542715220370688851293 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Subsequence of A060885. From Bernard Schott, Nov 01 2019: (Start) These are the primes associated with the terms k of A308238. A162861 = A286301 Union {this sequence}. The numbers of this sequence R_11 = 11111111111_k with k > 1 are Brazilian primes, so belong to A085104. (End) LINKS Chai Wah Wu, Table of n, a(n) for n = 1..1658 FORMULA {A060885(A018252(n)) which are in A000040}. EXAMPLE 10778947368421 is in the sequence since 10778947368421 = 20^10 + 20^9 + 20^8 + 20^7 + 20^6 + 20^5 + 20^4 + 20^3 + 20^2 + 20 + 1, 20 is not prime, and 10778947368421 is prime. MAPLE f:= proc(n) local p, j; if isprime(n) then return NULL fi; p:= add(n^j, j=0..10); if isprime(p) then p else NULL fi end proc: map(f, [\$1..1000]); # Robert Israel, Nov 19 2014 PROG (Python) from sympy import isprime A198244_list, m = [], [3628800, -15966720, 28828800, -27442800, 14707440, -4379760, 665808, -42240, 682, 0, 1] for n in range(1, 10**4): ....for i in range(10): ........m[i+1]+= m[i] ....if not isprime(n) and isprime(m[-1]): ........A198244_list.append(m[-1]) # Chai Wah Wu, Nov 09 2014 (MAGMA) [a: n in [0..500] | not IsPrime(n) and IsPrime(a) where a is (n^10+n^9+n^8+n^7+n^6+n^5+n^4+n^3+n^2+n+1)]; // Vincenzo Librandi, Nov 09 2014 (PARI) forcomposite(n=0, 10^3, my(t=sum(k=0, 10, n^k)); if(isprime(t), print1(t, ", "))); \\ Joerg Arndt, Nov 10 2014 CROSSREFS Cf. A162861, A000040, A088548, A192321, A102909, A060885, A308238. Similar to A185632 (k^2+ ...), A193366 (k^4+ ...), A194194 (k^6+ ...). Sequence in context: A213647 A072218 A046844 * A066953 A213645 A257139 Adjacent sequences:  A198241 A198242 A198243 * A198245 A198246 A198247 KEYWORD nonn AUTHOR Jonathan Vos Post, Dec 21 2012 EXTENSIONS a(5)-a(6) from Robert G. Wilson v, Dec 21 2012 a(7) from Michael B. Porter, Dec 27 2012 Corrected terms a(6)-a(7) and added terms by Chai Wah Wu, Nov 09 2014 STATUS approved

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Last modified April 19 12:35 EDT 2021. Contains 343114 sequences. (Running on oeis4.)