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A284046
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Numbers k, not ending in 0, such that the consecutive digits of k^2 differ by 0 or 1.
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0
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1, 2, 3, 11, 26, 111, 1111, 11111, 105462, 111111, 460688, 753576, 1111111, 2806538, 3513626, 5858612, 11111111, 23335688, 111111111, 674874474, 8226042716, 2131535935501, 81655720279388
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OFFSET
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1,2
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COMMENTS
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Equivalently, numbers not ending in 0, whose square belong to A032981.
All members k ending in 1 are generators of infinite numbers of the form k*10^e which satisfy the same property. In a sense, here we list only "primitive" terms, not ending in 0.
a(24) > 10^17, if it exists.
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LINKS
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EXAMPLE
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81655720279388 belongs to this sequence because the consecutive digits of its square, 6667656654345656676777654544, differ by 0 or 1.
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MATHEMATICA
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Select[Range[10^6], Mod[#, 10] > 0 && Max@ Abs@ Differences@ IntegerDigits[ #^2] <= 1 &]
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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STATUS
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approved
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