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 A147524 #11 Aug 27 2024 21:40:32 %S A147524 1,1,1,2,2,5,3,12,7,21,12,55,18,122,41,171,85,474,121,1033,248,1479, %T A147524 527,3914,769,7258,1817,11637,3401,29836,4168,63073,11221,92425,22357, %U A147524 190248,31464,446565,76142,679451,129236,1680187,169804,3489610,440212,4451195 %N A147524 As a vector, shifts to the left when multiplied by A054521. %C A147524 Begin with (1, 1, 1), then the next term = dot product of current series and the corresponding row of A054521. %C A147524 Eigensequence of triangle A054521. %e A147524 a(5) = 2 = (1, 1, 1, 2) dot (1, 0, 1, 0) = (1 + 0 + 1 + 0). %o A147524 (Python) %o A147524 from math import gcd %o A147524 a = [1] %o A147524 for n in range (1, 45): %o A147524 a.append(sum(a[k] for k in range(n) if gcd(k+1, n) == 1)) %o A147524 print(a) # _Andrey Zabolotskiy_, Aug 27 2024 %Y A147524 Cf. A054521. %K A147524 nonn %O A147524 1,4 %A A147524 _Gary W. Adamson_, Apr 24 2009 %E A147524 Corrected and extended by _Andrey Zabolotskiy_, Aug 27 2024