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 A322585 a(n) = 1 if n is a product of primorial numbers (A002110), 0 otherwise. 7
 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1 COMMENTS Characteristic function of A025487, first differences of A085089. a(n) = 1 if n = 2^e1 * 3^e2 * ... * prime(k)^e_k, with k = A061395(n) = A001221(n) and e1 >= e2 >= ... >= e_k, 0 otherwise. LINKS Antti Karttunen, Table of n, a(n) for n = 1..83160 FORMULA For all n, a(n) >= A322586(n). PROG (PARI) A322585(n) = { my(f = factor(n)); for(i=1, #f~, if((primepi(f[i, 1])!=i)||((i>1)&&(f[i-1, 2]

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Last modified September 20 22:20 EDT 2019. Contains 327252 sequences. (Running on oeis4.)