Search: id:A060728 Results 1-1 of 1 results found. %I A060728 %S A060728 3,4,5,7,15 %N A060728 Numbers n such that Ramanujan's equation x^2 + 7 = 2^n has an integer solution. %C A060728 See A038198 for corresponding x. - Lekraj Beedassy (blekraj(AT)yahoo.com), Sep 07 2004 %C A060728 Also numbers such that 2^(n-3)-1 is in A000217, i.e. a triangular number. - M. F. Hasler, Feb 23 2009 %D A060728 J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 181, p. 56, Ellipses, Paris 2008. %D A060728 J. Roberts, Lure of the Integers. pp. 90-91, MAA 1992. %D A060728 T. Skolem, S. Chowla and D. J. Lewis, "The Diophantine Equation 2^(n+2)-7=x^2 and Related Problems.", Proc. Amer. Math. Soc. 10 (1959) 663-669, available at http://www.jstor.org/stable/2033452 [M. F. Hasler, Feb 23 2009] %H A060728 Anonymous, Developing a general 2nd degree Diophantine Equation x^2 + p = 2^n %H A060728 M. Beeler, R. W. Gosper and R. Schroeppel, HAKMEM: item 31: A Ramanujan Problem (R. Schroeppel) %H A060728 T. Do, Developing A General 2nd Degree Diophantine Equation x^2 + p = 2^n %H A060728 G. Myerson, Bibliography %H A060728 S. Ramanujan, Journal of the Indian Mathematical Society, Question 464(v,120) %H A060728 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics %H A060728 Eric Weisstein's World of Mathematics, Diophantine Equation 2nd Powers %e A060728 The fifth and ultimate solution to Ramanujan's equation is obtained for the 15-th power of 2, so that we have x^2 + 7 = 2^15 yielding x = 181. %Y A060728 Cf. A038198. %Y A060728 Sequence in context: A079463 A101759 A089560 this_sequence A101761 A035359 A143593 %Y A060728 Adjacent sequences: A060725 A060726 A060727 this_sequence A060729 A060730 A060731 %K A060728 fini,full,nonn %O A060728 1,1 %A A060728 Lekraj Beedassy (blekraj(AT)yahoo.com), Apr 25 2001 %E A060728 Added keyword "full" and reference to Skolem et al. - M. F. Hasler (MHasler(AT)univ-ag.fr), Feb 23 2009 Search completed in 0.001 seconds