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A233003
(n!)^2 mod Pt(n), where Pt(n) is product of first n positive triangular numbers (A000217).
0
0, 1, 0, 36, 900, 8100, 0, 25401600, 514382400, 12859560000, 6224027040000, 56016243360000, 9466745127840000, 1855482045056640000, 0, 6679735362203904000000, 13513104637738497792000000, 156365925093831188736000000, 225792395835492236534784000000, 22579239583549223653478400000000
OFFSET
1,4
COMMENTS
Indices of zeros appear to be 2^k-1.
EXAMPLE
a(4) = 1*4*9*16 mod 1*3*6*10 = 576 mod 90 = 36.
PROG
(Python)
s=t=1
for n in range(1, 33):
s*=n*n
t*=n*(n+1)/2
print str(s%t)+', ',
CROSSREFS
Cf. A006472 (triangular factorial, essentially equal to Pt(n)).
Cf. A006788 (floor(n!^2/Pt)).
Sequence in context: A169836 A335220 A248108 * A075916 A062150 A011811
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Dec 03 2013
STATUS
approved