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A122213 a(n) = (sum of the divisors of n)th integer from among those positive integers which are coprime to n. 1
1, 5, 5, 13, 7, 35, 9, 29, 19, 43, 13, 83, 15, 55, 44, 61, 19, 115, 21, 103, 55, 79, 25, 179, 38, 89, 59, 129, 31, 269, 33, 125, 79, 113, 69, 271, 39, 125, 89, 223, 43, 335, 45, 183, 146, 149, 49, 371, 66, 231, 113, 211, 55, 359, 98, 279, 125, 185, 61, 629, 63, 197, 181 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..63.

EXAMPLE

8 = 1 + 7 is the sum of the divisors of 7. 1,2,3,4,5,6,8,9,10,11,12,13,15,16,... are the positive integers

which are coprime to 7. Of these integers, 9 is the 8th. So a(7) = 9.

MATHEMATICA

f[n_] := Block[{c = DivisorSigma[1, n], k = 0}, While[c > 0, k++; While[GCD[n, k] > 1, k++ ]; c-- ]; k ]; Table[f[n], {n, 63}] (* Ray Chandler, Aug 29 2006 *)

CROSSREFS

Cf. A122212.

Sequence in context: A302676 A339947 A206553 * A224067 A049735 A055526

Adjacent sequences: A122210 A122211 A122212 * A122214 A122215 A122216

KEYWORD

nonn

AUTHOR

Leroy Quet, Aug 26 2006

EXTENSIONS

Extended by Ray Chandler, Aug 29 2006

STATUS

approved

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Last modified January 29 17:05 EST 2023. Contains 359923 sequences. (Running on oeis4.)