

A132068


Irregular array: row n has A000010(n) terms: the sum of the first m terms of row n is the mth positive integer which is coprime to n.


0



1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 2, 1, 2, 1, 1, 2, 4, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 2, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 4, 2, 2, 1, 1, 2, 3, 1, 3, 2, 1, 1, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 2, 4, 2, 4, 1, 1, 1
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OFFSET

1,6


COMMENTS

The first term of each row is 1. The sum of the terms of row n is n1, for n>=2. After the initial 1, the remaining terms of each row are the same forward or backward.


LINKS

Table of n, a(n) for n=1..105.


EXAMPLE

The positive integers which are <= 12 and are coprime to 12 are 1,5,7,11. Row 12 of the array is: 1,4,2,4. So we have: 1=1; 1+4=5; 1+4+2=7; 1+4+2+4=11.
The first 12 rows of the array:
1;
1;
1,1;
1,2;
1,1,1,1;
1,4;
1,1,1,1,1,1;
1,2,2,2;
1,1,2,1,2,1;
1,2,4,2;
1,1,1,1,1,1,1,1,1,1;
1,4,2,4


MATHEMATICA

f[n_] := Block[{g}, g = Select[Range[n], GCD[ #, n] == 1 &]; g  Prepend[Most[g], 0]]; Flatten[Array[f, 25]] (* Ray Chandler, Nov 01 2007 *)


CROSSREFS

Cf. A038566, A000010.
Sequence in context: A247487 A010248 A325403 * A173441 A326851 A129192
Adjacent sequences: A132065 A132066 A132067 * A132069 A132070 A132071


KEYWORD

nonn,tabf


AUTHOR

Leroy Quet, Oct 30 2007


EXTENSIONS

Extended by Ray Chandler, Nov 01 2007


STATUS

approved



