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A369788 Number of different coefficient values in expansion of Product_{k=1..n} (1+x^prime(k)). 2

%I #13 Feb 01 2024 20:20:36

%S 1,2,2,3,3,3,5,5,8,11,17,27,38,66,85,121,152,185,216,249,285,325,363,

%T 406,449,499,549,601,654,709,765,829,894,963,1032,1107,1182,1261,1342,

%U 1426,1512,1602,1692,1788,1884,1983,2082,2188,2299,2413,2527,2644,2763,2884,3009

%N Number of different coefficient values in expansion of Product_{k=1..n} (1+x^prime(k)).

%o (PARI) a(n) = #Set(Vec(prod(k=1, n, 1+x^prime(k))));

%o (Python)

%o from collections import Counter

%o from sympy import prime

%o def A369788(n):

%o c = {0:1}

%o for k in range(1,n+1):

%o m, d = prime(k), Counter(c)

%o for j in c:

%o d[j+m] += c[j]

%o c = d

%o return len(set(c.values()))+int(max(c)+1>len(c)) # _Chai Wah Wu_, Feb 01 2024

%Y Cf. A000040, A000586, A007504, A369789.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Feb 01 2024

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Last modified August 30 07:09 EDT 2024. Contains 375532 sequences. (Running on oeis4.)