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A273663
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Least monotonic left inverse for A273670: a(1) = 0; for n > 1, a(n) = A257680(A225901(n)) + a(n-1).
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16
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0, 0, 1, 2, 3, 3, 4, 4, 5, 6, 7, 7, 8, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 18, 18, 19, 20, 21, 21, 22, 22, 23, 24, 25, 25, 26, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 35, 36, 36, 37, 38, 39, 39, 40, 40, 41, 42, 43, 43, 44, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 53, 54, 54, 55, 56, 57, 57, 58, 58, 59, 60, 61, 61
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OFFSET
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1,4
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LINKS
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FORMULA
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Other identities.
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PROG
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(Scheme, with memoization-macro definec)
(Python)
from sympy import factorial as f
def a007623(n, p=2): return n if n<p else a007623(n//p, p+1)*10 + n%p
def a225901(n):
s=0
k=2
while n:
d=n%k
n=n//k
if d: s=s+(k - d)*f(k - 1)
k+=1
return s
def a257680(n): return 1 if '1' in str(a007623(n)) else 0
def a(n): return 0 if n==1 else a257680(a225901(n)) + a(n - 1)
l=[0, 0]
for n in range(2, 101): l.append(a257680(a225901(n)) + l[n - 1])
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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