A033863 Least number of Sort-then-add persistence n.

1, 10, 65, 64, 175, 98, 240, 325, 302, 387, 198, 180, 550, 806, 855, 486, 351, 315, 944, 2428, 2204, 3172, 1793, 1316, 937, 2775, 1815, 1461, 2541, 9378, 13327, 9638, 8149, 6581, 46965, 23487, 12198, 10599, 10920, 52345, 48788, 180666, 174870, 291119, 155563, 915443

Offset

0,2

Links

Michael S. Branicky, Table of n, a(n) for n = 0..100

Sean A. Irvine, Java program (github).

Eric Weisstein's World of Mathematics, Sort-Then-Add Sequence.

Prog

(Python)
from itertools import count, islice
def agen(LIMIT):
    adict, n = dict(), 0
    for k in count(1):
        c, m = 0, k
        while c <= LIMIT and m != (s:=int("".join(sorted(str(m))))):
            m += s; c += 1
        if c not in adict:
            adict[c] = k
            while n in adict and n <= LIMIT: yield adict[n]; n += 1
            if n > LIMIT: return
print(list(agen(40))) # Michael S. Branicky, Jan 16 2024

Crossrefs

Cf. A033909, A033908.

Sequence in context: A352113 A286070 A033908 * A233246 A229996 A255245

Adjacent sequences: A033860 A033861 A033862 * A033864 A033865 A033866

Keyword

nonn,base

Author

David W. Wilson

Extensions

a(44)-a(45) from Sean A. Irvine, Jul 26 2020

Status

approved