A261474 Number of binary strings of length n+7 such that the smallest number whose binary representation is not visible in the string is 9.

0, 2, 12, 52, 168, 461, 1133, 2612, 5759, 12309, 25666, 52509, 105803, 210655, 415349, 812461, 1578752, 3050921, 5868562, 11244267, 21472441, 40887802, 77668032, 147222550, 278556477, 526215993, 992694708, 1870443330, 3520594166, 6620431857, 12439538938

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Formula

G.f.: (x^28 +x^27 -3*x^26 +4*x^25 +12*x^24 -20*x^23 -8*x^22 +55*x^21 -37*x^20 -85*x^19 +123*x^18 +21*x^17 -208*x^16 +117*x^15 +166*x^14 -227*x^13 -17*x^12 +235*x^11 -108*x^10 -122*x^9 +134*x^8 +8*x^7 -86*x^6 +31*x^5 +21*x^4 -18*x^3 +12*x^2 -8*x+2)*x / ((x+1) *(x^2-x+1) *(x^2+x-1) *(x^4-x^3+2*x-1) *(x^5+x^4+x-1) *(x^5+x^2+x-1) *(x^4-x^3+x^2+x-1) *(x^3+x^2-1) *(x^4+x-1) *(x-1)^3).

a(n) = A261019(n+7,9).

Crossrefs

Column k=9 of A261019.

Sequence in context: A300572 A176580 A179259 * A350653 A080675 A218782

Adjacent sequences: A261471 A261472 A261473 * A261475 A261476 A261477

Keyword

nonn,easy

Author

Alois P. Heinz, Aug 20 2015

Status

approved