A004099 Sum of digits of Euler numbers.

1, 1, 1, 2, 5, 7, 7, 11, 17, 25, 13, 29, 29, 34, 46, 38, 41, 61, 61, 65, 62, 70, 85, 74, 83, 88, 91, 110, 113, 124, 106, 128, 170, 142, 157, 164, 128, 178, 172, 146, 176, 178, 178, 209, 206, 214, 247, 218, 263, 268, 235, 335, 284, 259, 295, 254, 278, 295, 283, 254, 308, 313

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• base

Links

• Chai Wah Wu, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000111, A007953.

Programs

Maple

b:= proc(n, k) option remember; `if`(k=0,
     `if`(n=0, 1, 0), b(n, k-1)+b(n-1, n-k))
    end:
a:= proc(n) option remember;
      add(i,i=convert(b(n$2), base, 10))
    end:
seq(a(n), n=0..100);  # Alois P. Heinz, Apr 17 2023

Python

from itertools import accumulate, islice
def A004099_gen(): # generator of terms
    yield from (1,1)
    blist = (0,1)
    while True:
        blist = tuple(accumulate(reversed(blist),initial=0))
        yield sum(int(d) for d in str(blist[-1]))
A004099_list = list(islice(A004099_gen(),30)) # Chai Wah Wu, Apr 17 2023

Formula

a(n) = A007953(A000111(n)).