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A219999 Decades whose prime pattern is the same as prime pattern in the previous decade.

%I A219999 #15 Jun 13 2025 07:39:11
%S A219999 38,79,114,125,134,135,140,155,168,181,219,235,249,277,289,292,311,
%T A219999 315,324,332,348,375,419,431,437,445,477,485,500,513,525,533,537,546,
%U A219999 559,561,576,597,610,617,625,641,649,651,675,693,697,707,709,714,718,727
%N A219999 Decades whose prime pattern is the same as prime pattern in the previous decade.
%H A219999 V. Raman, <a href="/A219999/b219999.txt">Table of n, a(n) for n = 1..10000</a>
%F A219999 a(n) >> n log^2 n.
%F A219999 a(n) = A216287(n) + 1.
%e A219999 The primes between 380 and 390 are 383 and 389. The primes in the previous decade are 373 and 379. Therefore 38 is in the sequence.
%t A219999 Select[Range[2, 1000], Mod[Prime[Range[PrimePi[NextPrime[10#]], PrimePi[10# + 10]]], 10] == Mod[Prime[Range[PrimePi[NextPrime[10# - 10]], PrimePi[10#]]], 10] &] (* _Alonso del Arte_, Dec 07 2012 *)
%o A219999 (PARI) for(i=2, 1000, if( isprime(10*i-9)==isprime(10*i+1) && isprime(10*i-7)==isprime(10*i+3) && isprime(10*i-3)==isprime(10*i+7) && isprime(10*i-1)==isprime(10*i+9), print1(i", ")))
%Y A219999 Cf. A190639.
%Y A219999 Cf. A216287 (lower decade).
%K A219999 nonn,base
%O A219999 1,1
%A A219999 _V. Raman_, Dec 07 2012