Example image of eyePlorer eyePlorer map for '42 (number)': 41 (number) 43 (number) Natural number The Hitchhiker's Guide to the Galaxy Abundant number Factorization Sphenic number Aliquot 30 (number) Twin prime Aliquot sequence Primary pseudoperfect number Sylvester's sequence Euler's totient function Bernoulli number Heptagon Noncrossing partition Tree (graph theory) Bernhard Riemann Moment (mathematics) Riemann zeta function Infinite product Polygonal number Pronic number Meander (mathematics) Størmer number International Mathematical Olympiad United States of America Mathematical Olympiad Harshad number Repdigit Self number Magic cube Atomic number Molybdenum Antipodes Earth Lewis Carroll Sylvie and Bruno 25924 Douglasadams Apparent magnitude Constellation Douglas Adams Messier object New General Catalogue Orion (constellation) Orion Nebula Pegasus (constellation) Spiral galaxy Brian G. Marsden Minor Planet Center