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A145838 Primes in A005891 = Centered pentagonal numbers: (5n^2 + 5n + 2)/2. 2

%I #8 Feb 12 2019 08:45:27

%S 31,181,331,601,1051,1381,3331,4951,5641,5881,9151,11731,12781,14251,

%T 17431,17851,19141,21391,31081,33931,41281,43891,51481,52201,61231,

%U 63601,67651,70141,70981,84181,92641,100501,104551,107641,116101,126001

%N Primes in A005891 = Centered pentagonal numbers: (5n^2 + 5n + 2)/2.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CenteredPentagonalNumber.html">Centerd Pentagonal Number</a>

%p A005891 := proc(n) (5*n*(n+1)+2)/2 ; end: for n from 1 to 1000 do c := A005891(n) ; if isprime(c) then printf("%d,",c) ; fi; od: # _R. J. Mathar_, Nov 02 2008

%Y Cf. A005891 = Centered pentagonal numbers: (5n^2 + 5n + 2)/2.

%K nonn

%O 1,1

%A _Alexander Adamchuk_, Oct 21 2008

%E More terms from _R. J. Mathar_, Nov 02 2008

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)