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A228587
Sum of the squares (modulo n) of the odd numbers less than n.
1
0, 1, 1, 2, 5, 5, 7, 4, 12, 25, 22, 22, 39, 49, 35, 40, 68, 69, 76, 50, 91, 77, 92, 44, 125, 169, 144, 182, 203, 205, 186, 208, 242, 289, 245, 210, 333, 285, 286, 180, 410, 413, 430, 374, 420, 529, 423, 376, 490, 625, 578, 546, 689, 585, 605, 476, 760, 841, 767, 710
OFFSET
1,4
COMMENTS
Sum over the odd-numbered columns in row n of A048152.
FORMULA
a(n) = sum_{k=1,3,5,...,n-1} (k^2 mod n).
a(n) <= A048153(n).
A187468(n) = a(2^n).
MAPLE
A228587 := proc(n)
local a, o ;
a := 0 ;
for o from 1 to n-1 by 2 do
a := a+ modp(o^2, n) ;
end do:
a ;
end proc:
CROSSREFS
Cf. A000447.
Sequence in context: A332525 A196608 A129228 * A021395 A004599 A197695
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Aug 27 2013
STATUS
approved