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A040026
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If n=r*2^s, r odd, then a(n)=t*r, where t is smallest (in magnitude) number such that 1=t*r+u*2^s.
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0
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1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 11, -3, 13, 7, 15, 1, 17, 9, 19, 5, 21, 11, 23, 9, 25, 13, 27, -7, 29, 15, 31, 1, 33, 17, 35, 9, 37, 19, 39, -15, 41, 21, 43, -11, 45, 23, 47, -15, 49, 25, 51, 13, 53, 27, 55, -7, 57, 29, 59, -15, 61, 31, 63, 1, 65, 33, 67, 17, 69, 35, 71, 9, 73, 37, 75, -19
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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REFERENCES
| J. Neukirch, Class Field Theory, Springer, p. 1.
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EXAMPLE
| 24=3*2^3, 1=3*3-1*2^3, a(24)=3*3=9.
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PROG
| (C:) for(n=1; n<=100; n++) { r=n; s=1; while((r&1)==0) { r>>=1; s<<=1; } for(t=1; t<9999; t++) { if(((t*r-1)%s)==0) { printf("%d, ", t*r); break; } if(((t*r+1)%s)==0) { printf("%d, ", -t*r); break; } } if((n%10)==0) printf("\n"); if(t==9999) exit(0); //"not found": error }
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CROSSREFS
| |a(n)| differs from A000265, as a(24)=9.
Sequence in context: A161955 A000265 A106617 * A106609 A171968 A093474
Adjacent sequences: A040023 A040024 A040025 * A040027 A040028 A040029
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KEYWORD
| sign,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from Arlin Anderson (starship1(AT)gmail.com)
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