This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A261894 Number of compositions of n where the (possibly scattered) maximal subsequence of part i with multiplicity j is marked with a word of length j over an a(i-1)-ary alphabet whose letters appear in alphabetical order. 2
 1, 1, 2, 5, 14, 42, 131, 425, 1405, 4768, 16355, 57112, 200908, 715945, 2563950, 9275069, 33670472, 123183827, 451968108, 1668602686, 6173397451, 22959862085, 85535398344, 320037864300, 1199162682255, 4509735549128, 16979368985245, 64134400212097 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..1000 EXAMPLE a(4) = 14: 4a, 4b, 4c, 4d, 4e, 3a1a, 3b1a, 1a3a, 1a3b, 22aa 2a11aa, 12a1aa, 11aa2a, 1111aaaa. a(5) = 42: 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m, 5n, 4a1a, 4b1a, 4c1a, 4d1a, 4e1a, 1a4a, 1a4b, 1a4c, 1a4d, 1a4e, 3a2a, 3b2a, 2a3a, 2a3b, 3a11aa, 3b11aa, 13a1aa, 13b1aa, 11aa3a, 11aa3b, 22aa1a, 21a2aa, 1a22aa, 2a111aaa, 12a11aaa, 112a1aaa, 111aaa2a, 11111aaaaa. a(6) = 131: 6a, ..., 33aa, 33ab, 33bb, ..., 111111aaaaaa. The marked composition 33ba is not in this list. MAPLE b:= proc(n, i, p) option remember; `if`(n=0, p!,       `if`(i<1, 0, add((t-> binomial(t+j-1, t-1))(        a(i-1))*b(n-i*j, i-1, p+j)/j!, j=0..n/i)))     end: a:= n-> b(n\$2, 0): seq(a(n), n=0..30); CROSSREFS Cf. A000108 (without order restriction), A032009 (with distinct parts). Sequence in context: A261588 A006930 A036767 * A287969 A061922 A293498 Adjacent sequences:  A261891 A261892 A261893 * A261895 A261896 A261897 KEYWORD nonn,eigen AUTHOR Alois P. Heinz, Sep 05 2015 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 December 7 05:14 EST 2019. Contains 329839 sequences. (Running on oeis4.)