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 A247861 Prime sieve of Phi. 3

%I

%S 1,80,3988,49,4848,4,86,6,8,7720309,62862,54486,526046,890244,0,20,

%T 893,48,540,17,38622,5369,31800,6,54,86,958,56,226,92,0,5,2501,3,

%U 43216,548626296,61,8,7,1,40805,9544,492,8,5364864,443,344,495658,88,8,39,254,706,15884607,88712,5,7,41662,40,0,2,7,77,15,14,1704666

%N Prime sieve of Phi.

%H Manfred Scheucher, <a href="/A247861/b247861.txt">Table of n, a(n) for n = 1..385</a>

%H Manfred Scheucher, <a href="/A247861/a247861.sage.txt">Sage Script</a>

%e Find the first occurrence of prime 2 in the digits of Phi (only 40 digits in this illustration):

%e 161803398874989484820458683436563811772..., and replace it with a space:

%e 1618033988749894848 0458683436563811772... Repeat the process with 3:

%e 16180 3988749894848 0458683436563811772... Then 5:

%e 16180 3988749894848 04 8683436563811772... Then 7:

%e 16180 3988 49894848 04 8683436563811772... Then 11, 13, 17, etc., until the first occurrence of every prime is eliminated from the digits of Phi.

%e 1 80 3988 49 4848 04 86 6 8 772... Then consolidate gaps between the remaining digits into a single comma:

%e 1,80,3988,49,4848,4,86,6,8,7720309,... to produce the first terms in the prime sieve of Phi.

%Y Cf. A001622, A247747, A245770.

%K nonn,easy

%O 1,2

%A _Gil Broussard_, Sep 25 2014

%E Corrected and extended by _Manfred Scheucher_, Jun 05 2015

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Last modified September 15 22:10 EDT 2019. Contains 327088 sequences. (Running on oeis4.)