The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A255407 Permutation of natural numbers: a(n) = A255127(A252460(n)). 17
 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 23, 20, 21, 22, 25, 24, 19, 26, 27, 28, 29, 30, 37, 32, 33, 34, 35, 36, 41, 38, 39, 40, 43, 42, 47, 44, 45, 46, 53, 48, 31, 50, 51, 52, 61, 54, 49, 56, 57, 58, 67, 60, 71, 62, 63, 64, 65, 66, 77, 68, 69, 70, 83, 72, 89, 74, 75, 76, 59, 78, 91, 80, 81 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) tells which number in Ludic array A255127 is at the same position where n is in array A083221, the sieve of Eratosthenes. As both arrays have A005843 (even numbers) and A016945 as their two topmost rows, both sequences are among the fixed points of this permutation. Equally: a(n) tells which number in array A255129 is at the same position where n is in the array A083140, as they are the transposes of above two arrays. LINKS Antti Karttunen, Table of n, a(n) for n = 1..8192 FORMULA a(n) = A255127(A252460(n)). Other identities. For all n >= 1: a(2n) = 2n. [Fixes even numbers.] a(3n) = 3n. [Fixes multiples of three.] a(A008578(n)) = A003309(n). [Maps noncomposites to Ludic numbers.] a(A001248(n)) = A254100(n). [Maps squares of primes to "postludic numbers".] a(A084967(n)) = a(5*A007310(n)) = A007310((5*n)-3) = A255413(n). [Maps A084967 to A255413.] (And similarly between other columns and rows of A083221 and A255127.) EXAMPLE A083221(8,1) = 19 and A255127(8,1) = 23, thus a(19) = 23. A083221(9,1) = 23 and A255127(9,1) = 25, thus a(23) = 25. A083221(3,2) = 25 and A255127(3,2) = 19, thus a(25) = 19. PROG (define (A255407 n) (A255127 (A252460 n))) CROSSREFS Cf. A001248, A003309, A007310, A008578, A083221, A084967, A252460, A254100, A255413, A255127. Inverse: A255408. Similar permutations: A249818. Sequence in context: A246093 A261924 A255421 * A269171 A269395 A302025 Adjacent sequences:  A255404 A255405 A255406 * A255408 A255409 A255410 KEYWORD nonn AUTHOR Antti Karttunen, Feb 22 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 22 17:18 EDT 2021. Contains 345388 sequences. (Running on oeis4.)