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 A180270 Integers of the form (k^12 - k^8 - k^4 + 1)/512. 1
 0, 1025, 476073, 27022500, 551536100, 6129324225, 45502479225, 253405810448, 1137920432400, 4322847530025, 14366776735025, 42801847892100, 116415023802948, 293153032943225, 691043521403025, 1538402208782400 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS B. Berselli, Table of n, a(n) for n = 1..100000. [From Bruno Berselli, Sep 21 2010] FORMULA Integers of the form (k^4+1)*( (k-1)*(k+1)*(k^2+1) )^2/512. a(n) = ((2*n-1)^4+1)*((n-1)*n*(n^2+(n-1)^2))^2/8 (for k=2n-1). a(n) = A175110(n-1)*(A001844(n-1)*A000217(n-1))^2. - Bruno Berselli, Sep 21 2010 EXAMPLE a(2) = 1025 is in the sequence because (3^12 - 3^8 - 3^4 + 1)/512 = 524800/512 = 1025. MAPLE for n from 1 by 2 to 60 do: x:= (n^12-n^8 -n^4+1)/512: printf(`%d, `, x):od: # incomplete program which also prints rationals, R. J. Mathar MATHEMATICA Select[Table[(k^12-k^8-k^4+1)/512, {k, 40}], IntegerQ]  (* Harvey P. Dale, Jan 23 2011 *) CROSSREFS Sequence in context: A279643 A168119 A272672 * A103716 A291508 A031530 Adjacent sequences:  A180267 A180268 A180269 * A180271 A180272 A180273 KEYWORD nonn,easy AUTHOR Michel Lagneau, Aug 23 2010 EXTENSIONS Comment converted to formula by R. J. Mathar, Aug 25 2010 Example corrected and general term of the sequence rewritten by Bruno Berselli, Sep 22 2010 STATUS approved

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Last modified February 28 08:28 EST 2020. Contains 332323 sequences. (Running on oeis4.)