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A061099
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Squares with digital root 1.
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1
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1, 64, 100, 289, 361, 676, 784, 1225, 1369, 1936, 2116, 2809, 3025, 3844, 4096, 5041, 5329, 6400, 6724, 7921, 8281, 9604, 10000, 11449, 11881, 13456, 13924, 15625, 16129, 17956, 18496, 20449, 21025, 23104, 23716, 25921, 26569, 28900, 29584
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = (9*n+2)^2/4 for n even; a(n)=(9*n+7)^2/4 for n odd.
G.f.: x*(1+63*x+34*x^2+63*x^3+x^4)/((1-x)^3*(1+x)^2). (End)
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EXAMPLE
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289 = 17^2, 2+8+9 = 19, 1+9 = 1, 1369 = 37^2, 1+3+6+9 = 19, 1+9 = 1.
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PROG
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CROSSREFS
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KEYWORD
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nonn,base,easy,changed
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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