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A080339
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Characteristic function of {1} union {primes}: 1 if n is 1 or a prime, else 0.
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6
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1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Partial sums of a(n) in A036234. [From Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Mar 23 2009]
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LINKS
| Index entries for characteristic functions
Eric Weisstein's World of Mathematics, Prime Formulas
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FORMULA
| a(n)=Sum_digits{binomial(n! mod (n+1),n)}, with n>=0 - Paolo P. Lava (paoloplava(AT)gmail.com), Apr 24 2007
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MAPLE
| P:=proc(n) local i, k, w; for i from 0 by 1 to n do w:=0; k:=binomial(i! mod (i+1), i); while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; print(w); od; end: P(1000); - Paolo P. Lava (paoloplava(AT)gmail.com), Apr 24 2007
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MATHEMATICA
| Table[Which[n==1, 1, PrimeQ[n], 1, True, 0], {n, 110}] (* From Harvey P. Dale, Oct 03 2011 *)
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CROSSREFS
| Cf. A010051, A080355.
Cf. A036234. [From Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Mar 23 2009]
Sequence in context: A082416 A093996 A083187 * A167752 A100923 A050073
Adjacent sequences: A080336 A080337 A080338 * A080340 A080341 A080342
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Mar 21 2003
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