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 A027830 Numbers k such that k + (k+1)^2 + (k+2)^3 + (k+3)^4 + (k+4)^5 is prime. 0
 1, 7, 11, 25, 35, 43, 45, 47, 51, 53, 57, 63, 65, 81, 91, 103, 113, 117, 121, 143, 149, 169, 173, 191, 193, 199, 201, 211, 213, 225, 235, 247, 253, 255, 263, 269, 299, 331, 333, 355, 357, 359, 373, 385, 387, 395, 399, 403, 411, 445, 453, 495, 519, 537, 579, 599 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Numbers k such that A027622(k) is prime. LINKS Table of n, a(n) for n=1..56. P. De Geest, Palindromic Quasi_Under_Squares of the form n+(n+1)^2 EXAMPLE k=1: k + (k+1)^2 + (k+2)^3 + (k+3)^4 + (k+4)^5 = 3413 = A027886(1), k=7: k + (k+1)^2 + (k+2)^3 + (k+3)^4 + (k+4)^5 = 171851 = A027886(2), k=11: k + (k+1)^2 + (k+2)^3 + (k+3)^4 + (k+4)^5 = 800143 = A027886(3). MATHEMATICA With[{c=Total[Table[(#+i)^(i+1), {i, 0, 4}]]}, Select[Range[600], PrimeQ[c]&]] (* Harvey P. Dale, May 07 2012 *) PROG (Magma) [n: n in [0..1000] |IsPrime(n+(n+1)^2+(n+2)^3+(n+3)^4+(n+4)^5)] // Vincenzo Librandi, Nov 20 2010 (PARI) is(n)=isprime(n+(n+1)^2+(n+2)^3+(n+3)^4+(n+4)^5) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A027622, A027886. Sequence in context: A160054 A359414 A247590 * A134043 A102373 A002643 Adjacent sequences: A027827 A027828 A027829 * A027831 A027832 A027833 KEYWORD nonn,easy AUTHOR Patrick De Geest EXTENSIONS Edited by N. J. A. Sloane, May 21 2008 at the suggestion of R. J. Mathar STATUS approved

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Last modified April 23 07:34 EDT 2024. Contains 371905 sequences. (Running on oeis4.)