cp's OEIS Frontend

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.

A115453 Primes formed from the initial digits of sqrt(2).

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%I A115453 #23 Jul 09 2025 12:50:11
%S A115453 1414213562373095048801688724209698078569671875376948073
%N A115453 Primes formed from the initial digits of sqrt(2).
%C A115453 A115377 gives the number of digits in a(n).
%C A115453 Next terms have 97, 225, 11260 and 11540 digits and are therefore too big to include on a single line.
%H A115453 Amiram Eldar, <a href="/A115453/b115453.txt">Table of n, a(n) for n = 1..3</a>
%H A115453 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/NonRecursions.html">Non Recursions</a>.
%H A115453 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ConstantPrimes.html">Constant Primes</a>.
%H A115453 <a href="/index/O#oneterm">Index entries for one-term sequences</a>.
%F A115453 a(n) = floor(sqrt(2) * 10^(A115377(n)-1)). - _Amiram Eldar_, Jul 09 2025
%t A115453 Select[Floor[Sqrt[2]*10^Range[0,225]], PrimeQ] (* _Amiram Eldar_, Jul 09 2025 *)
%Y A115453 Cf. A002193, A115377.
%K A115453 nonn,base,bref
%O A115453 1,1
%A A115453 _Eric W. Weisstein_, Jan 22 2006
%E A115453 Definition corrected by _Charles R Greathouse IV_, Jul 24 2009