This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A249342 #11 Oct 26 2014 20:51:46 %S A249342 1,2,6,13,20,39,45,70,80,97,121,145,193,240,257,296,322,379,400,432, %T A249342 481,490,532,566,632,715,760,766,807,835,878,1067,1104,1209,1215,1369, %U A249342 1414,1468,1514,1540,1605,1683,1706,1853,1871,1905,1935,2116,2276,2293,2304,2343 %N A249342 Position of the first occurrence of n-th noncomposite number, A008578(n), in A249337; positions of records in A249072. %F A249342 For all n >= 1: %F A249342 A249337(a(n)) = A008578(n). %F A249342 A249072(a(n)) = n-1. %F A249342 For all n >= 2: %F A249342 a(n) = A249341(n) - 1. %o A249342 (Scheme, with _Antti Karttunen_'s IntSeq-library, two alternative definitions) %o A249342 (define A249342 (MATCHING-POS 1 1 (lambda (n) (or (= 1 n) (and (= 1 (A249337 (+ 1 n))) (prime? (A249337 n))))))) %o A249342 (define A249342 (RECORD-POS 1 1 A249072)) %Y A249342 After the initial term, one less than A249341. %Y A249342 Cf. A008578, A249337, A249340, A249072. %K A249342 nonn %O A249342 1,2 %A A249342 _Antti Karttunen_, Oct 26 2014