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Search: id:A159952
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| A159952 |
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Numbers n with property that sod(n^2)=sod(n)^2, sod(n) = sum of digits of n = A007953(n), sod(n^2)= A004159(n). |
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+0
1
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| 0, 1, 2, 3, 10, 11, 12, 13, 20, 21, 22, 30, 31, 100, 101, 102, 103, 110, 111, 112, 113, 120, 121, 122, 130, 200, 201, 202, 210, 211, 212, 220, 221, 300, 301, 310, 311, 1000, 1001, 1002, 1003, 1010, 1011, 1012, 1013, 1020, 1021, 1022, 1030, 1031, 1100, 1101, 1102
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OFFSET
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1,3
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COMMENT
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1. Numbers n with property that A004159(n)=(A007953(n))^2.
2. If we omit terms t>0 such that mod(t,10)=0 then sequence coinsides with A085305 (proof needed!-ZS).
3. There are 616 terms <=10^6 and 1436 terms <=10^7.
4. Only digits {0,1,2,3} seem to arise - exactly as in A085305.
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FORMULA
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Union of {0} and A061909. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 29 2009]
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CROSSREFS
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A085305 Solutions to rev[x^2]=rev[x]^2. A004159 Sum of digits of n^2. A007953 Digital sum (i.e.sum of digits) of n. A058369 Numbers n such that n and n^2 have same digit sum.
Sequence in context: A123977 A069967 A061909 this_sequence A007961 A060811 A146327
Adjacent sequences: A159949 A159950 A159951 this_sequence A159953 A159954 A159955
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KEYWORD
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base,nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Apr 27 2009
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