A248831 Prime sieve of the square root of 2.
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
Offset: 1
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)
Programs
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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
Extensions
More terms from David Consiglio, Jr., Dec 02 2014, Jan 03 2015
More terms from Manfred Scheucher, May 25 2015
Comments