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A201123
Differences between odd powers of 7 and the next smaller square.
2
3, 19, 166, 894, 5703, 12654, 620046, 4235622, 24518766, 133763479, 575536407, 7275224659, 63521178243, 36407018199, 1783943891751, 12048048160062, 62797942092807, 615169213046419, 4293026969512678, 29406470217788179, 174254081653289398, 2627356192258967382
OFFSET
1,1
LINKS
FORMULA
a(n) = 7^(2*n-1) - floor(sqrt(7^(2*n-1)))^2.
EXAMPLE
a(1)=7^1-2^2=3, a(2)=7^3-18^2=343-324=19, a(3)=7^5-129^2=16807-16641=166.
MATHEMATICA
Table[7^(2 n - 1) - Floor[Sqrt[7^(2 n - 1)]]^2, {n, 30}] (* Wesley Ivan Hurt, Mar 06 2014 *)
CROSSREFS
Cf. A051218.
Sequence in context: A183069 A256710 A215093 * A260700 A105624 A238640
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Nov 27 2011
STATUS
approved