login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

a(1) = 1, for n>=2: a(n) = sum of two consecutive noncomposite numbers A008578.
2

%I #23 Nov 05 2023 09:03:56

%S 1,3,5,8,12,18,24,30,36,42,52,60,68,78,84,90,100,112,120,128,138,144,

%T 152,162,172,186,198,204,210,216,222,240,258,268,276,288,300,308,320,

%U 330,340,352,360,372,384,390,396,410,434,450,456,462,472,480,492,508

%N a(1) = 1, for n>=2: a(n) = sum of two consecutive noncomposite numbers A008578.

%C Basically these are the sums of two successive primes. - _N. J. A. Sloane_, Nov 16 2018

%C Essentially the same as A001043, A011974 and A069102.

%H Paolo Xausa, <a href="/A164653/b164653.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A158611(n) + A158611(n+1).

%F a(n) = A008578(n-1) + A008578(n) for n >= 2.

%F a(n) = A076273(n-1) + 1 for n >= 2.

%F a(n) = A000040(n-1) + A008578(n-1) for n >= 2. - _Jaroslav Krizek_, Dec 13 2009

%t ListConvolve[{1,1},Join[{0,1},Prime[Range[100]]]] (* _Paolo Xausa_, Nov 02 2023 *)

%Y Cf. A000040, A001043, A008578, A011974, A069102, A076273, A158611.

%K nonn

%O 1,2

%A _Jaroslav Krizek_, Aug 19 2009

%E Edited by _R. J. Mathar_, Aug 21 2009

%E Correction for change of offset in A158611 and A008578 in Aug 2009 by _Jaroslav Krizek_, Jan 27 2010

%E Formulas edited by _Paolo Xausa_, Nov 04 2023