OFFSET
0,4
COMMENTS
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..10000 (terms 0..5000 from Alois P. Heinz)
FORMULA
Aerate and convolve sequences are generated by triangles (in this case A174066) in which ongoing terms are placed in the left column and at the top as a heading. Columns >1 are shifted down k times (k=2) in this case corresponding to (k-1) interpolated zeros. Next term in left column = n-th term in the "target sequence" S(n) (in this case A000041) minus (sum of terms in n-th row for columns >1). Place the latter term in the heading filling in missing terms.
G.f.: Product_{i>=1, j>=0} (1 + x^(i*4^j)). - Ilya Gutkovskiy, Sep 23 2019
a(n) ~ exp(2*Pi*sqrt(n)/3) / (2^(11/8) * 3^(3/4) * n^(7/8)). - Vaclav Kotesovec, Sep 24 2019
From Seiichi Manyama, May 31 2024: (Start)
G.f.: Product_{k>=1} (1 + x^k)^(valuation(k,4) + 1).
Let A(x) be the g.f. of this sequence, and B(x) be the g.f. of A000009, then B(x) = A(x)/A(x^4). (End)
EXAMPLE
1, 1, 1, 2, 3, 4,.... = heading
1;................... = 1
1;................... = 1
1, 1;................ = 2
2, 1;................ = 3
3, 1, 1;............. = 5
4, 2, 1;............. = 7
5, 3, 1, 2;.......... = 11
7, 4, 2, 2;.......... = 15
9, 5, 3, 2, 3;....... = 22
...
... where terms in the left column are the result of the two rules: multiply heading * left column, and row sums = partition numbers.
Thus leftmost term in column 8 must be 7 = 15 - (4 + 2 + 2). Then the 7 is placed in its spot in the left column and as the next heading term.
MAPLE
p:= combinat[numbpart]:
a:= proc(n) option remember; `if`(n=0, 1, p(n)-add(a(j)*
`if`(irem(n-j, 2, 'r')=1, 0, a(r)), j=0..n-1))
end:
seq(a(n), n=0..61); # Alois P. Heinz, Jul 27 2019
MATHEMATICA
nmax = 60; CoefficientList[Series[Product[QPochhammer[-1, x^(4^j)]/2, {j, 0, Log[nmax]/Log[4]}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Sep 24 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Mar 06 2010
EXTENSIONS
More terms from R. J. Mathar, Mar 18 2010
Offset corrected by Alois P. Heinz, Jul 27 2019
STATUS
approved