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 A248831 Prime sieve of the square root of 2. 5
 1, 4, 1, 6, 309, 6, 8078, 1875, 69480, 66, 7, 32, 8462, 388, 87, 2764, 27350, 846, 12, 24, 6055850, 4, 999358, 41322266, 27505, 9995050, 527820605, 470, 5, 716059, 453459686, 285, 86408, 5, 87, 4508, 627995, 8968, 396546, 808, 640620, 5, 50, 502, 599, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Algorithm: see A245770 (prime sieve of Pi). LINKS Manfred Scheucher, Table of n, a(n) for n = 1..431 Wikipedia, Square root of 2 Manfred Scheucher, Sage Script (Note: should also run in pure python with a few modifications) PROG (Python) def sqroot(a, digits): ....a = a * (10**(2*digits)) ....x_prev = 0 ....x_next = 1 * (10**digits) ....while x_prev != x_next: ........x_prev = x_next ........x_next = (x_prev + (a // x_prev)) >> 1 ....return x_next def primes(n): ....sieve = [True] * n ....for i in range(3, int(n**0.5)+1, 2): ........if sieve[i]: ............sieve[i*i::2*i]=[False]*((n-i*i-1)/(2*i)+1) ....return [2] + [i for i in range(3, n, 2) if sieve[i]] a = sqroot(2, 300)#300 digits is arbitrary - lengthen for more digits b = primes(10000000)#make sure to scan primes up to longest term in sequence y = str(a) for x in b: ....if str(x) in y: ........y = y.replace(str(x), " ", 1)#replace first occurrence only while "  " in y: ....y = y.replace("  ", " ")#replace chains of spaces with a single space z = y.split(" ")#split terms into a list z = filter(None, z)#remove null terms f = map(int, z)#convert to integers print(f) # David Consiglio, Jr., Jan 03 2015 CROSSREFS Cf. A002193 (square root of 2), A245770 (prime sieve of Pi), A248804 (prime sieve of e). Sequence in context: A191714 A126150 A291056 * A227729 A096966 A140703 Adjacent sequences:  A248828 A248829 A248830 * A248832 A248833 A248834 KEYWORD nonn,base AUTHOR Jared Kish, Oct 15 2014 EXTENSIONS More terms from David Consiglio, Jr., Dec 02 2014, Jan 03 2015 More terms from Manfred Scheucher, May 25 2015 STATUS approved

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Last modified April 11 02:21 EDT 2021. Contains 342886 sequences. (Running on oeis4.)