%I #8 Feb 17 2015 00:10:25
%S 0,1,3,6,7,11,14,15,19,23,27,30,31,35,39,44,47,51,55,59,62,63,67,71,
%T 76,79,86,91,95,99,103,108,111,115,119,123,126,127,131,135,140,143,
%U 150,155,159,166,172,176,182,187,191,195,199,204,207,214,219,223,227,231,236,239,243,247,251,254,255
%N Least inverse of A255072; a(n) = smallest k such that A255072(k) = n.
%C Also positions of records in A255072.
%H Antti Karttunen, <a href="/A255053/b255053.txt">Table of n, a(n) for n = 0..16143</a>
%F Other identities. For all n >= 0:
%F a(0) = 0; for n > 0: a(n) = a(n-1) + A255054(n-1).
%F a(n) = A255056(n) - A255123(n).
%o (Scheme, with _Antti Karttunen_'s IntSeq-library, four different implementations):
%o (define A255053 (MATCHING-POS 0 0 (lambda (i) (or (< i 1) (not (= (A255072 (- i 1)) (A255072 i)))))))
%o (define A255053 (LEAST-I-WITH-FUN-I-EQ-N 0 0 A255072)) ;; Slow!
%o (define A255053 (RECORD-POS 0 0 A255072))
%o (definec (A255053 n) (if (zero? n) n (+ (A255053 (- n 1)) (A255054 (- n 1)))))
%Y Cf. A255072, A255054, A255055, A255056, A255123.
%Y Analogous sequences: A213708, A219643, A219653.
%K nonn
%O 0,3
%A _Antti Karttunen_, Feb 14 2015