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A277959
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Numbers n such that 2 is the largest decimal digit of n^2.
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15
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11, 101, 110, 149, 1001, 1010, 1011, 1100, 1101, 1490, 10001, 10010, 10011, 10100, 10110, 11000, 11001, 11010, 14499, 14900, 100001, 100010, 100011, 100100, 100101, 100110, 101000, 101001, 101100, 110000, 110001, 110010, 110100, 144990, 149000, 316261
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listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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The terms > 1 of A058411 can be considered as primitive elements of this sequence, obtained by multiplying those by powers of 10 (cf. formula). These terms of A058411 have at least 2 nonzero digits, and therefore their square has at least one digit 2. - M. F. Hasler, Nov 15 2017
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LINKS
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FORMULA
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MATHEMATICA
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Select[Range[4*10^5], And[#[[2]] > 0, Union@ Take[RotateLeft[#, 2], 7] == {0}] &@ DigitCount[#^2] &] (* Michael De Vlieger, Nov 16 2017 *)
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PROG
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(PARI) L=List(); for(n=1, 10000, if(vecmax(digits(n^2))==2, listput(L, n))); Vec(L)
(PARI) A277959(LIM=1e15, L=List(), N=1)={while(LIM>N=next_A058411(N), my(t=N); until(LIM<t*=10, listput(L, t))); Set(L)} \\ M. F. Hasler, Nov 15 2017
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CROSSREFS
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Cf. A136808 and A136809, ..., A137147 for other digit combinations. (Numbers must satisfy the same restriction as their squares.)
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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