Search: id:A008578 Results 1-1 of 1 results found. %I A008578 %S A008578 1,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83, %T A008578 89,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,173,179, %U A008578 181,191,193,197,199,211,223,227,229,233,239,241,251,257,263,269,271 %N A008578 Prime numbers at the beginning of the 20th century (today 1 is no longer regarded as a prime). %C A008578 The non-composite numbers. %C A008578 Also smallest sequence with the property that the product of 2 or more elements with different indices is never a square. - Ulrich Schimke (ulrschimke(AT)aol.com), Dec 12 2001 %C A008578 Numbers n such that their largest divisor <= sqrt(n) equals 1. (See also A161344, A161345, A161424). [From Omar E. Pol (info(AT)polprimos.com), Jul 05 2009] %C A008578 Or numbers n with only perfect partition; also numbers such that 1=number of perfect partitions of n; or, unit together with the prime numbers A000040. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Sep 27 2009] %C A008578 d(n)<3 [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 17 2009] %D A008578 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 870. %D A008578 G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers. 3rd ed., Oxford Univ. Press, 1954, p. 11. %D A008578 H. D. Huskey, Derrick Henry Lehmer [1905-1991]. IEEE Ann. Hist. Comput. 17 (1995), no. 2, 64-68. Math. Rev. 96b:01035 %D A008578 D. H. Lehmer, The sieve problem for all-purpose computers. Math. Tables and Other Aids to Computation, Math. Tables and Other Aids to Computation, 7, (1953). 6-14. Math. Rev. 14:691e %D A008578 D. N. Lehmer, "List of Prime Numbers from 1 to 10,006,721", Carnegie Institute, Washington, D.C. 1909. %D A008578 R. F. Lukes, C. D. Patterson and H. C. Williams, Numerical sieving devices: their history and some applications. Nieuw Arch. Wisk. (4) 13 (1995), no. 1, 113-139. Math. Rev. 96m:11082 %D A008578 Williams, H. C.; Shallit, J. O. Factoring integers before computers. Mathematics of Computation 1943-1993: a half-century of computational mathematics (Vancouver, BC, 1993), 481-531, Proc. Sympos. Appl. Math., 48, AMS, Providence, RI, 1994. Math. Rev. 95m:11143 %H A008578 O. E. Pol, Determinacion geometrica de los numeros primos y perfectos [From Omar E. Pol (info(AT)polprimos.com), Jul 05 2009] %H A008578 O. E. Pol, Illustration: Divisors and pi(x) [From Omar E. Pol (info(AT)polprimos.com), Jul 05 2009] %H A008578 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. %H A008578 PrimeFan, Arguments for and against the primality of 1. %H A008578 G. P. Michon, Is 1 a prime number ? %H A008578 Wikipedia, Dirichlet convolution %H A008578 O. E. Pol, Illustration of initial terms [From Omar E. Pol (info(AT)polprimos.com), Oct 24 2009] %H A008578 O. E. Pol, Illustration for A008578, A161344, A161345 and A161424 [From Omar E. Pol (info(AT)polprimos.com), Oct 24 2009] %F A008578 m is in the sequence iff sigma(m)+phi(m)=2m. - Farideh Firoozbakht (mymontain(AT)yahoo.com), Jan 27 2005 %F A008578 a(n) = A158611(n+1) for n >= 1. [From Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Jun 19 2009] %F A008578 In the following formulas (based on emails from Jaroslav Krizek and R. J. Mathar), the star denotes a Dirichlet convolution between two sequences, and "This" is A008578. %F A008578 This = A030014 * A008683. (Dirichlet convolution using offset 1 with A030014) %F A008578 This = A030013 * A000012. (Dirichlet convolution using offset 1 with A030013) %F A008578 This = A034773 * A007427. (Dirichlet convolution) %F A008578 This = A034760 * A023900. (Dirichlet convolution) %F A008578 This = A034762 * A046692. (Dirichlet convolution) %F A008578 This * A000012 = A030014. (Dirichlet convolution using offset 1 with A030014) %F A008578 This * A008683 = A030013. (Dirichlet convolution using offset 1 with A030013) %F A008578 This * A000005 = A034773. (Dirichlet convolution) %F A008578 This * A000010 = A034760. (Dirichlet convolution) %F A008578 This * A000203 = A034762. (Dirichlet convolution) %F A008578 A002033(a(n))=1. [From Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Sep 27 2009] %p A008578 A008578 := n->if n=1 then 1 else ithprime(i-1); %t A008578 Join[ {1}, Table[ Prime[n], {n, 1, 60} ] ] %Y A008578 See A000040, which is the main entry for this sequence. The complement of A002808. %Y A008578 Cf. A161344, A161345, A161424, A161835. [From Omar E. Pol (info(AT)polprimos.com), Jul 05 2009] %Y A008578 Cf. A002033. [From Juri-stepan Gerasimov (2stepan(AT)rambler.ru), Sep 27 2009] %Y A008578 Cf. First column of array in A163280. Also, first row of array in A163990. [From Omar E. Pol (info(AT)polprimos.com), Oct 24 2009] %Y A008578 Sequence in context: A070159 A158611 A000040 this_sequence A100726 A015919 A064555 %Y A008578 Adjacent sequences: A008575 A008576 A008577 this_sequence A008579 A008580 A008581 %K A008578 nonn,easy,nice %O A008578 1,2 %A A008578 N. J. A. Sloane (njas(AT)research.att.com). %E A008578 Replaced a geocities.com URL - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 30 2009 Search completed in 0.003 seconds