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 A307730 #31 Dec 01 2024 10:03:36 %S A307730 1,2,2,3,3,3,6,4,4,4,4,6,6,6,6,6,9,9,9,9,9,9,9,9,9,12,8,8,8,8,8,8,8,8, %T A307730 12,12,12,12,12,12,12,12,12,12,12,15,5,5,5,5,5,7,7,7,7,7,7,7,14,10,10, %U A307730 10,10,10,10,10,10,10,10,14,14,14,14,14,14,14 %N A307730 a(n) = A307720(n) * A307720(n+1). %C A307730 For all positive integers n, n appears n times. %H A307730 Rémy Sigrist, <a href="/A307730/b307730.txt">Table of n, a(n) for n = 1..25000</a> %H A307730 Rémy Sigrist, <a href="/A307730/a307730.png">Scatterplot of the first 10000000 terms</a> %H A307730 Rémy Sigrist, <a href="/A307730/a307730.gp.txt">PARI program for A307730</a> %H A307730 N. J. A. Sloane, <a href="/A307730/a307730_1.txt">Table of n, a(n) for n = 1..999999</a> %e A307730 The first terms in this sequence and in A307720 are: %e A307730 n a(n) A307720(n) %e A307730 -- ---- ---------- %e A307730 1 1 1 %e A307730 2 2 1 %e A307730 3 2 2 %e A307730 4 3 1 %e A307730 5 3 3 %e A307730 6 3 1 %e A307730 7 6 3 %e A307730 8 4 2 %e A307730 9 4 2 %e A307730 10 4 2 %o A307730 (PARI) \\ See Links section. %o A307730 (Python) %o A307730 from itertools import islice %o A307730 from collections import Counter %o A307730 def A307730(): # generator of terms. Greedy algorithm %o A307730 c, b = Counter(), 1 %o A307730 while True: %o A307730 k, kb = 1, b %o A307730 while c[kb] >= kb: %o A307730 k += 1 %o A307730 kb += b %o A307730 c[kb] += 1 %o A307730 b = k %o A307730 yield kb %o A307730 A307730_list = list(islice(A307730(),100)) # _Chai Wah Wu_, Oct 21 2021 %Y A307730 Cf. A002024, A088178, A307720. %Y A307730 Cf. A348579 (indices of occurrence of each number), A348246 (first occurrence of each number), A348409 (last occurrence). %K A307730 nonn,hear %O A307730 1,2 %A A307730 _Rémy Sigrist_, Apr 25 2019