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A066566
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Numbers which when decremented by the sum of their digits produce a square.
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2
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 330, 331, 332, 333
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| The squares in this sequence are divisible by 9.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
| 155 is a member as 155-1-5-5=144=12^2.
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MATHEMATICA
| Select[Range[0, 350], IntegerQ[Sqrt[#-Total[IntegerDigits[#]]]]&] (* From Harvey P. Dale, Feb 24 2011 *)
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PROG
| (PARI): digitsum(n) = local(s, d); s=0; while(n>0, d=divrem(n, 10); n=d[1]; s=s+d[2]); s a066566(m)= local(n); for(n=0, m, if(issquare(n-digitsum(n)), print1(n, ", "))) a066566(7000)
(PARI) SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) } { n=0; for (m=0, 10^10, if (issquare(m - SumD(m)), write("b066566.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Mar 05 2010]
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CROSSREFS
| Cf. A066564.
Sequence in context: A059962 A057605 A110548 * A067080 A008554 A055644
Adjacent sequences: A066563 A066564 A066565 * A066567 A066568 A066569
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KEYWORD
| base,nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Dec 18 2001
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EXTENSIONS
| More terms from Jason Earls (zevi_35711(AT)yahoo.com), Dec 20 2001
OFFSET changed from 0,3 to 1,3 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Mar 05 2010
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