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A072300 Number of positive integers not exceeding n that are relatively prime to reverse(n). 0
1, 1, 2, 2, 4, 2, 6, 4, 6, 10, 10, 7, 13, 14, 10, 16, 17, 12, 16, 10, 7, 10, 12, 7, 12, 13, 9, 14, 14, 20, 29, 31, 20, 34, 35, 20, 37, 38, 25, 20, 18, 14, 21, 20, 15, 23, 23, 14, 24, 40, 27, 42, 37, 29, 40, 41, 30, 44, 45, 20, 31, 29, 21, 31, 28, 20, 32, 33, 23, 60, 67, 48, 72 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..73.

EXAMPLE

Among the positive integers not exceeding 12, the seven numbers 1,2,4,5,8,10,11 are relatively prime to reverse(12)=21. Hence a(12)=7.

MATHEMATICA

r = {}; Do[ s = FromDigits[Reverse[IntegerDigits[n]]]; j = 0; For[i = 1, i <= n, i++, If[GCD[s, i] == 1, j++ ]]; r = Append[r, j], {n, 1, 10^2}]; r

CROSSREFS

Cf. A000010.

Sequence in context: A063428 A133439 A234649 * A210359 A286553 A278222

Adjacent sequences:  A072297 A072298 A072299 * A072301 A072302 A072303

KEYWORD

base,nonn

AUTHOR

Joseph L. Pe, Jul 14 2002

STATUS

approved

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Last modified April 24 18:03 EDT 2019. Contains 322430 sequences. (Running on oeis4.)