A141479 a(n) = A000111(n) + A014695(n).

2, 3, 3, 3, 6, 18, 63, 273, 1386, 7938, 50523, 353793, 2702766, 22368258, 199360983, 1903757313, 19391512146, 209865342978, 2404879675443, 29088885112833, 370371188237526, 4951498053124098, 69348874393137903, 1015423886506852353

Offset

0,1

Comments

a(n) is a multiple of 3 for n > 0.

Links

Table of n, a(n) for n=0..23.

Maple

A000111 := proc(n) local x; n!*coeftayl( sec(x)+tan(x), x=0, n) ; end: A014695 := proc(n) local x; coeftayl( (1+2*x+2*x^2+x^3)/(1-x^4), x=0, n) ; end: A141479 := proc(n) A000111(n)+A014695(n) ; end: for n from 0 to 30 do printf("%a, ", A141479(n)) ; od; # R. J. Mathar, Sep 12 2008

Prog

(Python)
from itertools import count, islice, accumulate
def A141479_gen(): # generator of terms
    yield from (2, 3)
    blist = (0, 1)
    for n in count(0):
        yield (blist := tuple(accumulate(reversed(blist), initial=0)))[-1] + (2, 1, 1, 2)[n & 3]
A141479_list = list(islice(A141479_gen(), 40)) # Chai Wah Wu, Jun 09-11 2022

Crossrefs

Sequence in context: A070167 A168113 A170895 * A055081 A275379 A109833

Adjacent sequences: A141476 A141477 A141478 * A141480 A141481 A141482

Keyword

nonn,easy

Author

Paul Curtz, Aug 09 2008

Extensions

Extended by R. J. Mathar, Sep 12 2008

Status

approved