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A117893 Add up the positive integers which are coprime to n in order (starting at 1). a(n) is the smallest such partial sum that is >= n. +0
5
1, 4, 3, 4, 6, 6, 10, 9, 12, 11, 15, 13, 15, 18, 22, 16, 21, 24, 21, 20, 30, 25, 28, 24, 31, 36, 27, 29, 36, 32, 36, 36, 37, 36, 44, 37, 45, 49, 48, 44, 45, 47, 45, 53, 46, 49, 55, 54, 59, 61, 61, 68, 55, 54, 65, 57, 61, 64, 66, 68, 66, 64, 70, 64, 77, 85, 78, 83, 75, 73, 78, 73 (list; graph; listen)
OFFSET

1,2

COMMENT

a(2) = 1+3. Every other a(n) of the sequence involves only adding integers which are <= n.

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

EXAMPLE

12 is coprime to 1, 5, 7, 11,... Now 1 = 1, 1+5 = 6, 1+5+7 = 13, 1+5+7+11 = 24, ... 13 is the smallest such partial sum that is >= 12. So a(12) = 13.

MAPLE

printf("1, 4, ") ; for n from 3 to 60 do resul :=0 ; for m from 1 to 1000 do if gcd(n, m) <= 1 then resul := resul + m ; if resul >= n then printf("%a, ", resul) ; break ; fi ; fi ; od : od: - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 02 2006

MATHEMATICA

f[n_] := Block[{k = 1, s}, While[s = Plus @@ Select[Range[k], GCD[ #, n] == 1 &]; s < n, k++ ]; s]; Table[f[n], {n, 75}] (*Chandler*)

CROSSREFS

Cf. A117892, A125748, A125749.

Cf. A092933.

Sequence in context: A090369 A132293 A135103 this_sequence A021701 A097511 A021027

Adjacent sequences: A117890 A117891 A117892 this_sequence A117894 A117895 A117896

KEYWORD

nonn

AUTHOR

Leroy Quet Mar 30 2006

EXTENSIONS

More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 02 2006

a(61) and later terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Dec 11 2006

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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