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Search: id:A135190
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| A135190 |
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Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=5. |
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+0
17
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| 3, 12, 36, 42, 102, 162, 432, 468, 1002, 1026, 1080, 1188, 1215, 1380, 1512, 1620, 1770, 1950, 1980
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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3^1=3
3^2=9 and 9 is a multiple of 3
3^3=27 -> Sum_digits(27)=9 and 27 is a multiple of 9
3^4=81 -> Sum_digits(81)=9 and 81 is a multiple of 9
3^5=243 -> Sum_digits(243)=9 and 243 is a multiple of 9
3^6=729 -> Sum_digits(729)=18 and 729 is not a multiple of 18
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MAPLE
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readlib(log10); P:=proc(n, m) local a, i, k, w, x, ok; for i from 1 by 1 to n do a:=simplify(log10(i)); if not (trunc(a)=a) then ok:=1; x:=1; while ok=1 do w:=0; k:=i^x; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if trunc(i^x/w)=i^x/w then x:=x+1; else if x-1=m then print(i); fi; ok:=0; fi; od; fi; od; end: P(2000, 5);
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CROSSREFS
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Cf. A135186, A135187, A135188, A135189, A135191, A135192, A135193, A135194, A135195, A135196, A135197, A135198, A135199, A135200, A135201, A135202.
Sequence in context: A026573 A097339 A009787 this_sequence A101069 A167667 A027327
Adjacent sequences: A135187 A135188 A135189 this_sequence A135191 A135192 A135193
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KEYWORD
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easy,nonn,base
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AUTHOR
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Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Nov 22 2007
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