A343645 a(n) is the product of the frequencies of each digit of n up to and including that digit.

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

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