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 A343645 a(n) is the product of the frequencies of each digit of n up to and including that digit. 2
 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 12, 10, 12, 14, 16, 18, 20, 22, 24, 6, 52, 30, 21, 24, 27, 30, 33, 36, 39, 12, 70, 84, 56, 36, 40, 44, 48, 52, 56, 20, 90, 105, 120, 90, 55, 60, 65, 70, 75, 30, 112, 128, 144, 160, 132, 78, 84, 90, 96, 42, 136, 153, 170, 187, 204, 182 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,10 LINKS David A. Corneth, Table of n, a(n) for n = 1..10000 EXAMPLE a(10) = 2 as the digit 1 is the second digit 1 and the digit 0 is the first digit 0 giving 2*1. PROG (PARI) first(n) = my(v=vector(10), res=vector(n)); for(i=1, n, c=1; d=digits(i); for(i=1, #d, v[d[i]+1]++; c*=v[d[i]+1]); res[i] = c); res (Python) def aupto(limit): f, alst = [0 for i in range(10)], [] for n in range(1, limit+1): p = 1 for d in list(map(int, str(n))): f[d] += 1; p *= f[d] alst.append(p) return alst print(aupto(66)) # Michael S. Branicky, Apr 23 2021 CROSSREFS Sequence in context: A081468 A216349 A280015 * A245281 A358505 A308215 Adjacent sequences: A343642 A343643 A343644 * A343646 A343647 A343648 KEYWORD nonn,easy,base AUTHOR David A. Corneth, Apr 23 2021 STATUS approved

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Last modified March 5 09:44 EST 2024. Contains 370545 sequences. (Running on oeis4.)