cp's OEIS Frontend

A258193 Define a<+>b = odd part(odd part(a) + odd part(b)), where odd part(n) = A000265(n); a(n) is the smallest prime of the form <+>_{0<=i<=k} binomial (n,i), or a(n)=0 if there is no such a prime (see comment).

%I A258193 #16 Jun 20 2015 20:13:06
%S A258193 0,0,0,0,3,3,11,0,5,3,3,17,7,23,53,29,13,5,5,3,11,3,3,823,13,7,7,457,
%T A258193 109,109,233,2267,17,59,151,5,19,5,5,3,113,11,11,3,23,3,3,71,43,13,13,
%U A258193 7,179,7,7,193,29,2137,863,443,31,5498157739,977,163
%N A258193 Define a<+>b = odd part(odd part(a) + odd part(b)), where odd part(n) = A000265(n); a(n) is the smallest prime of the form <+>_{0<=i<=k} binomial (n,i), or a(n)=0 if there is no such a prime (see comment).
%C A258193 f(n)=<+>_{0<=i<=n} c(i) is defined as the following: f(0)=c(0), f(n)=f(n-1)<+>c(n).
%C A258193 a(n)=0 for 1,2,3,4,8,82,107,...(cf. A258194)
%H A258193 Peter J. C. Moses, <a href="/A258193/b258193.txt">Table of n, a(n) for n = 1..1000</a>
%t A258193 vSum[a_,b_]:=#[#[a]+#[b]]&[#/2^IntegerExponent[#,2]&];
%t A258193 Table[
%t A258193 First[Select[FoldList[vSum,First[#],Rest[#]]&[Map[Binomial[n,#]&,Range[0,n]]],PrimeQ]/.{}->{0}],{n,100}] (*_Peter J. C. Moses_, May 23 2015*)
%o A258193 (Haskell)
%o A258193 import Data.Function (on)
%o A258193 a258193 n = head $ (filter ((== 1) . a010051'') $
%o A258193                     scanl1 (<+>) (a034868_row n)) ++ [0]
%o A258193             where (<+>) = (a000265 .) . on (+) a000265
%o A258193 -- _Reinhard Zumkeller_, Jun 20 2015
%Y A258193 Cf. A000265, A007318, A258126, A258127, A258194.
%Y A258193 Cf. A034868, A010051.
%K A258193 nonn
%O A258193 1,5
%A A258193 _Vladimir Shevelev_, May 23 2015
%E A258193 More terms from _Peter J. C. Moses_, May 23 2015