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 A106571 Indices n of perfect squares n^2 which are not the difference of two primes. 17
 5, 7, 11, 13, 17, 19, 23, 25, 27, 29, 31, 35, 37, 41, 43, 47, 49, 51, 53, 55, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 83, 85, 87, 89, 91, 93, 95, 97, 101, 103, 107, 109, 113, 115, 119, 121, 125, 127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 149, 151, 153, 155 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also, n such that 1+n^2 is a nontotient (A005277). - T. D. Noe, Sep 13 2007 LINKS T. D. Noe, Table of n, a(n) for n=1..1000 FORMULA a(n) = sqrt(A106564(n)). EXAMPLE a(3)=11 because the third square which is not the difference of two primes (121=11^2) is the 11th one in the succession of the perfect squares (thus index 11). CROSSREFS Cf. A106544-A106548, A106562-A106564, A106573-A106575, A106577. Cf. A067201 (n such that n^2 + 2 is prime). Sequence in context: A322271 A306289 A136801 * A067291 A286265 A339911 Adjacent sequences:  A106568 A106569 A106570 * A106572 A106573 A106574 KEYWORD easy,nonn AUTHOR Alexandre Wajnberg, May 09 2005 EXTENSIONS Extended by Ray Chandler, May 12 2005 STATUS approved

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Last modified June 12 09:24 EDT 2021. Contains 344946 sequences. (Running on oeis4.)