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%I #26 Feb 19 2021 01:54:27
%S 10,60,52,68,131,112,128,223,172,97,420,113,127,407,149,308,330,352,
%T 181,780,0,211,679,472,241,508,532,548,564,293,307,941,0,668,696,712,
%U 367,752,772,397,810,419,421,1303,892,457,1391,479,487,990,1012,0,1044,0
%N a(n) = sum of primes in {10*n-9, 10*n-7, 10*n-3, 10*n-1}.
%F a(n) = (10n-9) isprime (10n-9) + (10n-7) isprime (10n-7) + (10n-3) isprime (10n-3) + (10n-1) isprime (10n-1), where isprime = A010051. - _M. F. Hasler_, Jun 15 2008
%e a(1) = 3 + 7 = 10.
%e a(11) = 101 + 103 + 107 + 109 = 420.
%e a(21) = 0 (there are no primes in {201, 203, 207, 209}).
%t f[n_]:=Plus@@Select[10n-{9,7,3,1},PrimeQ]; Table[f[n],{n,60}] (* _Ray Chandler_, Feb 20 2009 *)
%o (PARI) a(n)=(10*n-9)*isprime(10*n-9) + (10*n-7)*isprime(10*n-7) + (10*n-3)*isprime(10*n-3) + (10*n-1)*isprime(10*n-1) \\ _M. F. Hasler_, Jun 15 2008
%Y Cf. A030430, A030431, A030432, A030433.
%K nonn
%O 1,1
%A _Juri-Stepan Gerasimov_, Jul 06 2008
%E Corrected and extended by _Ray Chandler_, Feb 20 2009
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