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 A309891 a(n) is the total number of trailing zeros in the representations of n over all bases b >= 2. 2
 0, 1, 1, 3, 1, 3, 1, 5, 3, 3, 1, 6, 1, 3, 3, 8, 1, 6, 1, 6, 3, 3, 1, 9, 3, 3, 5, 6, 1, 7, 1, 10, 3, 3, 3, 11, 1, 3, 3, 9, 1, 7, 1, 6, 6, 3, 1, 13, 3, 6, 3, 6, 1, 9, 3, 9, 3, 3, 1, 12, 1, 3, 6, 14, 3, 7, 1, 6, 3, 7, 1, 15, 1, 3, 6, 6, 3, 7, 1, 13, 8, 3, 1, 12 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS a(n) depends only on the prime signature of n. LINKS Antti Karttunen, Table of n, a(n) for n = 1..16384 Antti Karttunen, Data supplement: n, a(n) computed for n = 1..100000 FORMULA a(n) = Sum_{d|n, d>1} A286561(n,d), where A286561 gives the d-valuation of n. a(p) = 1 for any prime number p. a(p^k) = A006218(k) for any k >= 0 and any prime number p. a(n) = 2^A001221(n) - 1 for any squarefree number n. a(n) = 3 for any semiprime number n. a(m*n) >= a(m) + a(n). a(n) >= A007814(n) + A007949(n) + A235127(n) + A112765(n) + A122841(n) + A214411(n) + A244413(n). a(n) = A056239(A293514(n)). - Antti Karttunen, Aug 22 2019 a(n) <= A033093(n). - Michel Marcus, Aug 22 2019 a(n) = A169594(n) - 1. - Jon Maiga, Aug 25 2019 EXAMPLE For n = 12: 12 has 2 trailing zeros in base 2 (1100), 1 trailing zero in bases 3, 4, 6 and 12 (110, 30, 20, 10) and no trailing zero in other bases, hence a(12) = 1*2 + 4*1 = 6. MATHEMATICA Table[DivisorSum[n, IntegerExponent[n, #] &, # > 1 &], {n, 84}] (* Jon Maiga, Aug 25 2019 *) PROG (PARI) a(n) = sumdiv(n, d, if (d>1, valuation(n, d), 0)) (PARI) a(n) = {if(n == 1, return(0)); my(f = factor(n)[, 2], res = 0, t = 2, of = f, nf = f >> 1, nd(v) = prod(i = 1, #v, v[i] + 1)); while(Set(of) != [0], res += (nd(of) - nd(nf)) * (t-1); of = nf; t++; nf = f \ t); res} \\ David A. Corneth, Aug 22 2019 CROSSREFS Cf. A001221, A006218, A007814, A007949, A033093, A056239, A112765, A122841, A169594, A214411, A235127, A244413, A286561, A293514. Sequence in context: A249947 A193583 A331731 * A317937 A322436 A013603 Adjacent sequences:  A309888 A309889 A309890 * A309892 A309893 A309894 KEYWORD nonn,base AUTHOR Rémy Sigrist, Aug 21 2019 STATUS approved

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Last modified July 25 01:26 EDT 2021. Contains 346273 sequences. (Running on oeis4.)