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A130008 Noncomposite numbers sandwiched between 1's. 2

%I

%S 1,1,1,2,1,3,1,5,1,7,1,11,1,13,1,17,1,19,1,23,1,29,1,31,1,37,1,41,1,

%T 43,1,47,1,53,1,59,1,61,1,67,1,71,1,73,1,79,1,83,1,89,1,97,1,101,1,

%U 103,1,107,1,109,1,113,1,127,1,131,1,137,1,139,1,149

%N Noncomposite numbers sandwiched between 1's.

%C A000012 and A008578 interleaved. - _Omar E. Pol_, Feb 05 2014

%e Difference array begins:

%e 1 1 1 2 1 3 1 5 1 7 1 11

%e .. 0 0 1 -1 2 -2 4 -4 6 -6 10

%e ..... 0 1 -2 3 -4 6 -8 10 -12 16

%e ........ 1 -3 5 -7 10 -14 18 -22 28

%Y Cf. A000040.

%K nonn,easy

%O 0,4

%A _Paul Curtz_, Jun 15 2007

%E More terms and definition corrected by _Omar E. Pol_, Feb 05 2014

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Last modified September 19 11:05 EDT 2019. Contains 327192 sequences. (Running on oeis4.)