login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A257762 Numbers n with property that A062234(n) = A062234(n+1). 8

%I #29 Sep 08 2022 08:46:12

%S 1,3,5,7,13,26,28,43,49,64,69,78,89,93,96,116,131,134,142,148,152,155,

%T 167,182,202,206,212,225,231,234,236,238,247,253,258,281,286,302,303,

%U 311,313,330,332,333,334,336,337,356,362,384,385,390,435,438,455,458,484,492,512,516

%N Numbers n with property that A062234(n) = A062234(n+1).

%C Numbers n with property that 2*prime(n)-prime(n+1) = 2*prime(n+1)-prime(n+2), or 2*prime(n)+prime(n+2) = 3*prime(n+1).

%C Numbers n with property that 2*A001223(n) = A001223(n+1). - _Gionata Neri_, May 22 2015

%C a(n) = A258432(m), where m such that A258383(m) = 2. - _Reinhard Zumkeller_, May 31 2015

%H Robert Israel, <a href="/A257762/b257762.txt">Table of n, a(n) for n = 1..10000</a>

%e a(1) = A258437(A258432(2)) = 1.

%p Primes:= select(isprime,[2,(2*i+1 $ i=1..10^4)]):

%p Gaps:= Primes[2..-1] - Primes[1..-2]:

%p G2:= Gaps[2..-1] - 2*Gaps[1..-2]:

%p ListTools:-SearchAll(0,G2); # _Robert Israel_, May 22 2015

%t Select[Range@ 600, 2 Prime[#] - Prime[# + 1] == 2 Prime[# + 1] - Prime[# + 2] &] (* _Michael De Vlieger_, May 11 2015 *)

%o (Magma) [n: n in [0..600] | 2*NthPrime(n)-NthPrime(n+1) eq 2*NthPrime(n+1)-NthPrime(n+2)]; // _Vincenzo Librandi_, May 12 2015

%o (Haskell)

%o a257762 n = a257762_list !! (n-1)

%o a257762_list = map a258432 $ filter ((== 2) . a258383) [1..]

%o -- _Reinhard Zumkeller_, May 31 2015

%Y Cf. A258383, A258432, A258437, A258469, A257762, A258449, A257892, A257951.

%K nonn

%O 1,2

%A _Zak Seidov_, May 07 2015

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 07:27 EDT 2024. Contains 371265 sequences. (Running on oeis4.)