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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.)