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 A324534 The smallest common prime factor of sigma(n) and A276086(n), or 1 if no such prime exists. 2
 1, 3, 2, 1, 2, 1, 2, 3, 1, 3, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 2, 5, 1, 3, 2, 1, 2, 1, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 1, 2, 3, 2, 3, 2, 1, 1, 3, 2, 7, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 1, 2, 1, 2, 3, 2, 3, 2, 5, 2, 3, 2, 5, 2, 7, 2, 3, 1, 3, 2, 7, 2, 3, 2, 3, 2, 1, 2, 3, 2, 3, 2, 7, 2, 3, 2, 7, 2, 1, 2, 3, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..30030 FORMULA a(n) = A020639(A324644(n)) = A020639(gcd(A000203(n),A276086(n))). PROG (PARI) A276086(n) = { my(i=0, m=1, pr=1, nextpr); while((n>0), i=i+1; nextpr = prime(i)*pr; if((n%nextpr), m*=(prime(i)^((n%nextpr)/pr)); n-=(n%nextpr)); pr=nextpr); m; }; A020639(n) = if(1==n, n, factor(n)[1, 1]); A324534(n) = A020639(gcd(sigma(n), A276086(n))); CROSSREFS Cf. A000203, A020639, A276086, A324644. Sequence in context: A175191 A328928 A342468 * A248505 A254629 A096248 Adjacent sequences:  A324531 A324532 A324533 * A324535 A324536 A324537 KEYWORD nonn AUTHOR Antti Karttunen, Mar 11 2019 STATUS approved

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Last modified September 21 07:28 EDT 2021. Contains 347596 sequences. (Running on oeis4.)