A352375 Sum of digits of A007618.

5, 1, 2, 4, 8, 7, 5, 10, 11, 13, 8, 16, 14, 10, 11, 4, 8, 7, 14, 10, 11, 13, 17, 7, 5, 10, 11, 13, 8, 16, 14, 19, 11, 13, 8, 16, 14, 19, 20, 13, 8, 16, 14, 19, 20, 13, 8, 16, 14, 19, 20, 22, 8, 16, 14, 19, 20, 22, 17, 16, 14, 19, 20, 13, 17, 16, 14, 19, 20, 13

Offset: 1

Author

Mateusz Pasternak, Mar 14 2022

Keywords

• nonn
• base

References

• D. R. Kaprekar, Puzzles of the Self-Numbers. 311 Devlali Camp, Devlali, India, 1959.

Links

• D. R. Kaprekar, The Mathematics of the New Self Numbers, 1963. [annotated and scanned]

Crossrefs

Cf. A007618, A007953.

Programs

PARI

lista(nn) = my(s, x=5); for(n=1, nn, print1(s=sumdigits(x), ", "); x+=s); \\ Jinyuan Wang, Mar 22 2022

Python

from itertools import islice
def A352375_gen(): # generator of terms
    a = 5
    while True:
        yield (s := sum(int(d) for d in str(a)))
        a += s
A352375_list = list(islice(A352375_gen(),20)) # Chai Wah Wu, Mar 29 2022

Formula

a(n) = A007953(A007618(n)).

a(n) = A007618(n+1)-A007618(n). - Chai Wah Wu, Mar 29 2022

Extensions

More terms from Jinyuan Wang, Mar 22 2022