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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.

A180405 Smallest integer not yet present in the sequence such that the sum of the first a(n) terms of the sequence is a prime.

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%I A180405 #37 Sep 26 2024 20:45:14
%S A180405 2,1,4,6,3,7,8,10,11,15,12,18,14,16,22,24,19,31,28,20,23,37,36,30,26,
%T A180405 34,29,35,42,38,40,32,39,45,52,44,54,46,56,60,43,51,50,64,84,48,49,53,
%U A180405 68,58,62,78,70,66,57,59,82,92,90,88,63,77,72,94,67,79,76,102,71,81,96,100
%N A180405 Smallest integer not yet present in the sequence such that the sum of the first a(n) terms of the sequence is a prime.
%C A180405 From an idea of _Eric Angelini_ with additional terms from _D. S. McNeil_.
%C A180405 The partial sums of the sequence are 2, 3, 7, 13, 16, 23, 31, 41, 52, ...
%C A180405 The sequence is self-descriptive and says that the 2nd, 1st, 4th, 6th, 3rd, 7th, etc, term in the partial sums, namely 3, 2, 13, 23, 7, 31 etc, are primes.
%H A180405 Neal Gersh Tolunsky, <a href="/A180405/b180405.txt">Table of n, a(n) for n = 1..10000</a>
%H A180405 Eric Angelini, <a href="http://www.cetteadressecomportecinquantesignes.com/SumDigitPrime.htm">The sum of the a(n) first digits of S is a prime</a>
%H A180405 Eric Angelini, <a href="/A180405/a180405.pdf">The sum of the a(n) first digits of S is a prime</a> [Cached copy, with permission]
%Y A180405 Cf. A054408, A171007 (digits version), A363379 (complement).
%K A180405 easy,nonn
%O A180405 1,1
%A A180405 _Paolo P. Lava_, Sep 02 2010
%E A180405 Examples replaced with a comment by _R. J. Mathar_, Nov 18 2010