A124095 Happy numbers without zeros and with digits in nondecreasing order.

1, 7, 13, 19, 23, 28, 44, 49, 68, 79, 129, 133, 139, 167, 188, 226, 236, 239, 338, 356, 367, 368, 379, 446, 469, 478, 556, 566, 888, 899, 1112, 1114, 1115, 1122, 1125, 1128, 1148, 1158, 1177, 1188, 1222, 1233, 1247, 1257, 1258, 1277, 1288, 1299, 1333, 1335

Offset: 0

Author

Tanya Khovanova, Nov 25 2006

Keywords

• base
• nonn

Links

• Bryan Wolf, Table of n, a(n) for n = 0..13376 (terms < 10^10).
• Bryan Wolf, C++ program for generating happy numbers without zeros and with digits in non-decreasing order

Crossrefs

Cf. A007770 (Happy numbers), A068571, A219667.

Programs

Python

from itertools import count, islice, combinations_with_replacement
def A124095_gen(): # generator of terms
    for l in count(1):
        for m in combinations_with_replacement('123456789',l):
            k = t = int(''.join(m))
            while k not in {1,37,58,89,145,42,20,4,16}:
                k = sum((0, 1, 4, 9, 16, 25, 36, 49, 64, 81)[ord(d)-48] for d in str(k))
            if k == 1:
                yield t
A124095_list = list(islice(A124095_gen(),20)) # Chai Wah Wu, Aug 02 2023