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A249110
Numbers that form a Pythagorean 10-tuple with their first eight arithmetic derivatives.
3
4, 27, 3125, 398747, 823543
OFFSET
1,1
EXAMPLE
First eight arithmetic derivatives of 398747 are 1692, 2856, 5812, 5816, 8732, 9116, 9500, 15700 and sqrt(398747^2 + 1692^2 + 2856^2 + 5812^2 + 5816^2 + 8732^2 + 9116^2 + 9500^2 + 15700^2) = 399467.
MAPLE
with(numtheory);
Dr:=proc(w) local x, p; x:=w*add(op(2, p)/op(1, p), p=ifactors(w)[2]); end:
P:=proc(q, h) local a, b, k, n; for n from 2 to q do a:=n; b:=n^2;
for k from 1 to h do a:=Dr(a); b:=b+a^2; od; if type(sqrt(b), integer) then print(n);
fi; od; end: P(10^9, 8);
CROSSREFS
A051674 is a subsequence. - Ray Chandler, Dec 22 2016
Sequence in context: A066352 A357561 A249105 * A348329 A051674 A132641
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Oct 21 2014
STATUS
approved