cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A189936 Odd numbers in A076763.

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%I A189936 #20 Sep 15 2019 08:37:39
%S A189936 105,165,195,255,273,315,345,357,385,399,465,483,525,555,585,627,663,
%T A189936 693,705,735,765,777,795,897,915,957,975,1005,1095,1113,1155,1173,
%U A189936 1185,1281,1295,1305,1353,1365,1515,1545,1575,1617,1677,1683,1725,1755,1785,1815,1935,1953
%N A189936 Odd numbers in A076763.
%H A189936 G. C. Greubel, <a href="/A189936/b189936.txt">Table of n, a(n) for n = 1..5000</a>
%F A189936 a(n) = A005408(k) = A076763(m).
%p A189936 omega := proc(n) nops( numtheory[factorset](n)) ; end proc:
%p A189936 isA076763 := proc(n) omega(n) > omega(n-1) and omega(n) > omega(n+1) ; end proc:
%p A189936 isA189936 := proc(n) type(n,'odd') and isA076763(n) ; end proc:
%p A189936 for n from 1 to 2000 by 2 do if isA189936(n) then printf("%d,",n) ; end if; end do;  # _R. J. Mathar_, May 26 2011
%t A189936 Select[Range[1, 2000, 2], PrimeNu[# - 1] < PrimeNu[#] > PrimeNu[# + 1]&] (* _Jean-François Alcover_, Nov 14 2016 *)
%t A189936 Select[#[[2,1]]&/@Select[Partition[Table[{n,PrimeNu[n]},{n,2000}],3,1], #[[1,2]] <#[[2,2]]>#[[3,2]]&],OddQ] (* _Harvey P. Dale_, Sep 15 2019 *)
%Y A189936 Cf. A001221, A076763, A013590, A118678, A154430.
%K A189936 nonn
%O A189936 1,1
%A A189936 _Juri-Stepan Gerasimov_, May 01 2011
%E A189936 Corrected by _R. J. Mathar_, May 26 2011