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A062067
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a(1) = 1; a(n) is smallest square > a(n-1) such that a(n) + a(n-1) is a prime.
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3
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1, 4, 9, 64, 169, 400, 529, 900, 961, 1936, 2401, 5476, 6241, 6400, 7921, 9216, 10201, 10816, 11025, 13456, 14161, 15376, 17161, 17956, 19321, 19600, 22201, 22500, 24649, 24964, 27225, 29584, 29929, 31684, 33489, 40804, 41209, 52900
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OFFSET
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1,2
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LINKS
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EXAMPLE
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9 is the next term after 4 as 4+9 = 13 is a prime.
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MATHEMATICA
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sqrs=Range[400]^2;
nxt[n_]:=First[Select[sqrs, #>n&&PrimeQ[n+#]&]]
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PROG
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(PARI) p=1; n=2; for(k=1, 50, while(!isprime(p^2+n^2), n=n+1); print1(n^2", "); p=n; n=n+1)
(PARI) { a=b=1; for (n=1, 1000, if (n>1, until (isprime(a + b^2), b++)); write("b062067.txt", n, " ", a=b^2) ) } \\ Harry J. Smith, Jul 31 2009
(Python)
from sympy import isprime
for _ in range(1, 10000):
a += 1
b = 2*a*(a-1) + 1
while not isprime(b):
b += 4*(a+1)
a += 2
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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