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 A227349 Product of lengths of runs of 1-bits in binary representation of n. 28
 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 1, 2, 2, 2, 3, 4, 1, 1, 1, 2, 1, 1, 2, 3, 2, 2, 2, 4, 3, 3, 4, 5, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 1, 2, 2, 2, 3, 4, 2, 2, 2, 4, 2, 2, 4, 6, 3, 3, 3, 6, 4, 4, 5, 6, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 1, 2, 2, 2, 3, 4, 1, 1, 1, 2, 1, 1, 2, 3, 2, 2, 2, 4, 3, 3, 4, 5, 2, 2, 2, 4, 2, 2, 4, 6, 2, 2, 2, 4, 4, 4, 6, 8, 3, 3, 3, 6, 3, 3, 6, 9, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS This is the Run Length Transform of S(n) = {0, 1, 2, 3, 4, 5, 6, ...}. The Run Length Transform of a sequence {S(n), n >= 0} is defined to be the sequence {T(n), n >= 0} given by T(n) = Product_i S(i), where i runs through the lengths of runs of 1's in the binary expansion of n. E.g., 19 is 10011 in binary, which has two runs of 1's, of lengths 1 and 2. So T(19) = S(1)*S(2). T(0) = 1 (the empty product). - N. J. A. Sloane, Sep 05 2014 Like all run length transforms also this sequence satisfies for all i, j: A278222(i) = A278222(j) => a(i) = a(j). - Antti Karttunen, Apr 14 2017 LINKS Antti Karttunen, Table of n, a(n) for n = 0..8192 N. J. A. Sloane, On the Number of ON Cells in Cellular Automata, arXiv:1503.01168 [math.CO], 2015. FORMULA A167489(n) = a(n) * A227350(n). A227193(n) = a(n) - A227350(n). a(n) = Product_{i in row n of table A245562} i. - N. J. A. Sloane, Aug 10 2014 From Antti Karttunen, Apr 14 2017: (Start) a(n) = A005361(A005940(1+n)). a(n) = A284562(n) * A284569(n). A283972(n) = n - a(n). (End) EXAMPLE a(0) = 1, as zero has no runs of 1's, and an empty product is 1. a(1) = 1, as 1 is "1" in binary, and the length of that only 1-run is 1. a(2) = 1, as 2 is "10" in binary, and again there is only one run of 1-bits, of length 1. a(3) = 2, as 3 is "11" in binary, and there is one run of two 1-bits. a(55) = 6, as 55 is "110111" in binary, and 2 * 3 = 6. a(119) = 9, as 119 is "1110111" in binary, and 3 * 3 = 9. From Omar E. Pol, Feb 10 2015: (Start) Written as an irregular triangle in which row lengths is A011782: 1; 1; 1,2; 1,1,2,3; 1,1,1,2,2,2,3,4; 1,1,1,2,1,1,2,3,2,2,2,4,3,3,4,5; 1,1,1,2,1,1,2,3,1,1,1,2,2,2,3,4,2,2,2,4,2,2,4,6,3,3,3,6,4,4,5,6; ... Right border gives A028310: 1 together with the positive integers. (End) From Omar E. Pol, Mar 19 2015: (Start) Also, the sequence can be written as an irregular tetrahedron T(s, r, k) as shown below: 1; .. 1; .. 1; 2; .... 1,1; 2; 3; ........ 1,1,1,2; 2,2; 3; 4; ................ 1,1,1,2,1,1,2,3; 2,2,2,4; 3,3; 4; 5; ................................ 1,1,1,2,1,1,2,3,1,1,1,2,2,2,3,4; 2,2,2,4,2,2,4,6; 3,3,3,6; 4,4; 5; 6; ... Apart from the initial 1, we have that T(s, r, k) = T(s+1, r, k). (End) MAPLE a:= proc(n) local i, m, r; m, r:= n, 1;       while m>0 do         while irem(m, 2, 'h')=0 do m:=h od;         for i from 0 while irem(m, 2, 'h')=1 do m:=h od;         r:= r*i       od; r     end: seq(a(n), n=0..100);  # Alois P. Heinz, Jul 11 2013 ans:=[]; for n from 0 to 100 do lis:=[]; t1:=convert(n, base, 2); L1:=nops(t1); out1:=1; c:=0; for i from 1 to L1 do    if out1 = 1 and t1[i] = 1 then out1:=0; c:=c+1;    elif out1 = 0 and t1[i] = 1 then c:=c+1;    elif out1 = 1 and t1[i] = 0 then c:=c;    elif out1 = 0 and t1[i] = 0 then lis:=[c, op(lis)]; out1:=1; c:=0;    fi;    if i = L1 and c>0 then lis:=[c, op(lis)]; fi;                    od: a:=mul(i, i in lis); ans:=[op(ans), a]; od: ans;  # N. J. A. Sloane, Sep 05 2014 MATHEMATICA onBitRunLenProd[n_] := Times @@ Length /@ Select[Split @ IntegerDigits[n, 2], #[[1]] == 1 & ]; Array[onBitRunLenProd, 100, 0] (* Jean-François Alcover, Mar 02 2016 *) PROG (Python) from operator import mul from functools import reduce from re import split def A227349(n):     return reduce(mul, (len(d) for d in split('0+', bin(n)[2:]) if d)) if n > 0 else 1 # Chai Wah Wu, Sep 07 2014 (Sage) # uses[RLT from A246660] A227349_list = lambda len: RLT(lambda n: n, len) A227349_list(88) # Peter Luschny, Sep 07 2014 (Scheme) (define (A227349 n) (apply * (bisect (reverse (binexp->runcount1list n)) (- 1 (modulo n 2))))) (define (bisect lista parity) (let loop ((lista lista) (i 0) (z (list))) (cond ((null? lista) (reverse! z)) ((eq? i parity) (loop (cdr lista) (modulo (1+ i) 2) (cons (car lista) z))) (else (loop (cdr lista) (modulo (1+ i) 2) z))))) (define (binexp->runcount1list n) (if (zero? n) (list) (let loop ((n n) (rc (list)) (count 0) (prev-bit (modulo n 2))) (if (zero? n) (cons count rc) (if (eq? (modulo n 2) prev-bit) (loop (floor->exact (/ n 2)) rc (1+ count) (modulo n 2)) (loop (floor->exact (/ n 2)) (cons count rc) 1 (modulo n 2))))))) CROSSREFS Cf. A003714 (positions of ones), A005361, A005940. Cf. A000120 (sum of lengths of runs of 1-bits), A167489, A227350, A227193, A278222, A245562, A284562, A284569, A283972, A284582, A284583. Run Length Transforms of other sequences: A246588, A246595, A246596, A246660, A246661, A246674. Differs from similar A284580 for the first time at n=119, where a(119) = 9, while A284580(119) = 5. Sequence in context: A284569 A272604 A284580 * A246028 A232186 A340061 Adjacent sequences:  A227346 A227347 A227348 * A227350 A227351 A227352 KEYWORD nonn,base AUTHOR Antti Karttunen, Jul 08 2013 EXTENSIONS Data section extended up to term a(120) by Antti Karttunen, Apr 14 2017 STATUS approved

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Last modified September 24 03:26 EDT 2021. Contains 347623 sequences. (Running on oeis4.)