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A257764 Lexicographically largest increasing sequence of primes for which the continued square root map (see A257574) produces the decimal expansion of e (Euler's number). 4

%I #13 May 04 2018 11:26:35

%S 3,13,31,59,67,103,179,193,227,229,317,983,1201,1213,1321,1787,1811,

%T 2179,3571,4817,5333,6803,10433,12197,13063,19391,21283,24571,31817,

%U 42307,45377,49957,61909,67933,70573,74843,82421,85909,91099,99241,101293,109639,112087

%N Lexicographically largest increasing sequence of primes for which the continued square root map (see A257574) produces the decimal expansion of e (Euler's number).

%C Similar to A257582, but converging to e.

%H Chai Wah Wu, <a href="/A257764/b257764.txt">Table of n, a(n) for n = 1..1000</a>

%H Popular Computing (Calabasas, CA), <a href="/A257352/a257352.pdf">The CSR Function</a>, Vol. 4 (No. 34, Jan 1976), pages PC34-10 to PC34-11. Annotated and scanned copy.

%H Herman P. Robinson, <a href="/A257574/a257574.pdf">The CSR Function</a>, Popular Computing (Calabasas, CA), Vol. 4 (No. 35, Feb 1976), pages PC35-3 to PC35-4. Annotated and scanned copy.

%e sqrt(3) = 1.7320508075688772...

%e sqrt(3+sqrt(13)) = 2.570126704165378...

%e sqrt(3+sqrt(13+sqrt(31))) = 2.703522309917472...

%e sqrt(3+sqrt(13+sqrt(31+sqrt(59)))) = 2.7173508299457327...

%e sqrt(3+sqrt(13+sqrt(31+sqrt(59+sqrt(67))))) = 2.718217091497069...

%e sqrt(3+sqrt(13+sqrt(31+sqrt(59+sqrt(67+sqrt(103)))))) = 2.7182780002752187...

%o (PARI) (CSR(v, s)=forstep(i=#v, 1, -1, s=sqrt(v[i]+s)); s); a=[3]; for(n=1, 50, print1(a[#a]", "); for(i=primepi(a[#a])+1, oo, CSR(concat(a, vector(9, j, prime(i+j))))>=exp(1)&& (a=concat(a, prime(i)))&& break)) \\ The standard precision of 38 digits yields incorrect terms beyond 10433. Increase realprecision to compute larger values. - _M. F. Hasler_, May 03 2018

%Y Cf. A001113 (e), A257582 (analog for Pi instead of e), A257809 (analog for delta = 4.6692...), A257574.

%K nonn

%O 1,1

%A _Chai Wah Wu_, May 09 2015

%E Edited by _M. F. Hasler_, May 03 2018

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