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A073456 Numbers n such that to phi(n) = pi(n)+1. 3
1, 5, 36, 48, 84 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..5.

FORMULA

Solutions to A000010(x)=A000720(x)+k, where k=+1; finite for any fixed value of k.

EXAMPLE

15 primes below 48 = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47}; 16 terms in RRS[48]={1,5,7,11,13,17,19,23,25,29,31,35,37,41,43,47}, so 48 is here.

MATHEMATICA

Do[s=EulerPhi[n]-PrimePi[n]; If[Equal[s, 1], Print[n]], {n, 1, 10000}]

CROSSREFS

Cf. A037228, A037171, A000010, A000720, A073455.

Sequence in context: A263882 A035416 A042029 * A275223 A003350 A217166

Adjacent sequences:  A073453 A073454 A073455 * A073457 A073458 A073459

KEYWORD

fini,full,nonn

AUTHOR

Labos Elemer, Aug 02 2002

STATUS

approved

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Last modified May 19 03:12 EDT 2019. Contains 323377 sequences. (Running on oeis4.)