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 A257685 Left inverse for injection A255411: a(0) = 0, after which, if n = A255411(k) for some k, then a(n) = k, otherwise a(n) = 0. 5
 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 3, 0, 4, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 9, 0, 10, 0, 0, 0, 11, 0, 12, 0, 0, 0, 13, 0, 0, 0, 0, 0, 0, 0, 14, 0, 0, 0, 15, 0, 16, 0, 0, 0, 17, 0, 18, 0, 0, 0, 19, 0, 0, 0, 0, 0, 0, 0, 20, 0, 0, 0, 21, 0, 22, 0, 0, 0, 23, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,13 LINKS Antti Karttunen, Table of n, a(n) for n = 0..10080 FORMULA a(0) = 0, after which, if n = A255411(k) for some k, then a(n) = k, otherwise a(n) = 0. a(n) = (1-A257680(n)) * A257684(n). Other identities: For all n >= 0, a(A255411(n)) = n. [This sequence works as a left inverse of A255411.] MATHEMATICA Position[Select[Range[0, 120], ! MemberQ[IntegerDigits[#, MixedRadix[Reverse@ Range@ 12]], 1] &], #] - 1 & /@ Range[0, 120] /. {} -> 0 // Flatten (* Michael De Vlieger, May 30 2016, Version 10.2 *) PROG (Scheme) (define (A257685 n) (* (- 1 (A257680 n)) (A257684 n))) (Python) from sympy import factorial as f def a007623(n, p=2):     return n if n

0 else '0' for i in x)[::-1]     return 0 if n==1 else sum([int(y[i])*f(i + 1) for i in range(len(y))]) def a257680(n): return 1 if '1' in str(a007623(n)) else 0 def a(n): return (1 - a257680(n))*a257684(n) print([a(n) for n in range(101)]) # Indranil Ghosh, Jun 21 2017 CROSSREFS Cf. A255411, A257680, A257681, A257684. Sequence in context: A202425 A292374 A292376 * A327172 A113503 A082507 Adjacent sequences:  A257682 A257683 A257684 * A257686 A257687 A257688 KEYWORD nonn AUTHOR Antti Karttunen, May 04 2015 STATUS approved

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Last modified June 15 11:44 EDT 2021. Contains 345048 sequences. (Running on oeis4.)