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A073456
Numbers n such that to phi(n) = pi(n)+1.
3
1, 5, 36, 48, 84
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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
A344643
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 April 19 19:02 EDT 2024. Contains 371798 sequences. (Running on oeis4.)