The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A252746 Number of zeros on each row of irregular tables A252743 and A252744. 5
 1, 1, 1, 1, 2, 1, 6, 7, 10, 19, 26, 35, 56, 99, 154, 251, 437, 759, 1262, 1953, 2963, 4652, 7847, 13588 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Also, number of nodes on level n (the root 1 occurs at level 0) of binary tree depicted in A005940 where the left hand child is less than the right hand child of the node. E.g. on the level 2, containing nodes 3 and 4, the children of 3 are 5 < 6, and the children of 4 are 9 > 8, thus a(2) = 1. LINKS FORMULA a(n) = 2^(n-1) - A252745(n). PROG (PARI) allocatemem(234567890); A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ Using code of Michel Marcus A252746print(up_to_n) = { my(s, i=0, n=0); for(n=0, up_to_n, if(0 == n, s = 1; lev = vector(1); lev[1] = 2, oldlev = lev; lev = vector(2*length(oldlev)); s = 0; for(i = 0, (2^n)-1, lev[i+1] = if(!(i%2), A003961(oldlev[(i\2)+1]), 2*oldlev[(i\2)+1]); s += if((i%2), (lev[i+1] > lev[i]), 0))); write("b252746.txt", n, " ", s)); }; A252746print(23); \\ The terms a(0) .. a(23) were computed with this program. (Scheme) (define (A252746 n) (if (= 0 n) 1 (- (A000079 (- n 1)) (A252745 n)))) CROSSREFS Cf. A000079, A000225, A252737, A252743, A252744, A252745. Sequence in context: A160348 A047708 A256277 * A182883 A172285 A192232 Adjacent sequences:  A252743 A252744 A252745 * A252747 A252748 A252749 KEYWORD nonn,more AUTHOR Antti Karttunen, Dec 21 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 18 02:57 EST 2020. Contains 332006 sequences. (Running on oeis4.)