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.
%I A147850 #16 Aug 06 2017 21:38:24
%S A147850 1,0,1,0,1,0,0,1,1,0,0,1,0,1,0,1,1,1,1,1,1,0,1,1,0,1,1,0,0,0,0,1,0,1,
%T A147850 1,1,0,0,0,0,1,0,1,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,1,0,
%U A147850 1,1,0,0,1,1,0,0,1,1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,0,1,0,1,0,1,0,0,0,0,0,0
%N A147850 Parity of the digits sum of Sum_{j = 8*n-7..8*n} prime(j).
%F A147850 a(n) = 1 - A147781(n).
%F A147850 a(n) = A007953(17982*A127335(8*n-7)) mod 2. - _R. J. Mathar_, Jan 06 2009
%e A147850 2+3+5+7+11+13+17+19 = 1384614 (1+3+8+4+6+1+4) = 27 (1).
%e A147850 23+29+31+37+41+43+47+53 = 5466528 (5+4+6+6+5+2+8) = 36 (0).
%e A147850 461+463+467+479+487+491+499+503 = 69230700 (6+9+2+3+7) = 27 (1).
%e A147850 509+521+523+541+547+557+563+569 = 77862060 (7+7+8+6+2+6) = 36 (0).
%p A147850 A127335 := proc(n) add(ithprime(i),i=n..n+7) ; end:
%p A147850 A007953 := proc(n) add(i,i=convert(n,base,10)) ; end:
%p A147850 A147850 := proc(n) A007953(17982*A127335(8*n-7)) mod 2 ; end:
%p A147850 for n from 1 to 200 do printf("%a,",A147850(n)) ; od: # _R. J. Mathar_, Jan 06 2009
%Y A147850 Cf. A147781.
%K A147850 easy,nonn,base,less
%O A147850 1,1
%A A147850 _E.J.P. Vening_, Nov 15 2008
%E A147850 More terms from _R. J. Mathar_, Jan 06 2009