A227092 Numbers whose base-7 sum of digits is 7.

13, 19, 25, 31, 37, 43, 55, 61, 67, 73, 79, 85, 91, 103, 109, 115, 121, 127, 133, 151, 157, 163, 169, 175, 199, 205, 211, 217, 247, 253, 259, 295, 301, 349, 355, 361, 367, 373, 379, 385, 397, 403, 409, 415, 421, 427, 445, 451, 457, 463, 469, 493, 499, 505

Offset

1,1

Comments

All of the entries are odd.

Subsequence of A016921. - Michel Marcus, Sep 03 2013

In general, the set of numbers with sum of base-b digits equal to b is a subset of { (b-1)*k + 1; k = 2, 3, 4, ... }. - M. F. Hasler, Dec 23 2016

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Example

The 7-ary expansion of 13 is (1,6), which has sum of digits 7.
The 7-ary expansion of 103 is (2,0,5), which has sum of digits 7.
10 is not on the list since the 7-ary expansion of 10 is (1,3), which has sum of digits 4 not 7.

Mathematica

Select[Range[600], Total[IntegerDigits[#, 7]]==7&] (* Harvey P. Dale, Aug 18 2014 *)

Prog

(Sage)  [i for i in [0..1000] if sum(Integer(i).digits(base=7))==7]
(PARI) select( is(n)=sumdigits(n, 7)==7, [1..999]) \\ M. F. Hasler, Dec 23 2016
(Python)
agen = A226636gen(sod=7, base=7) # generator of terms using code in A226636
print([next(agen) for n in range(1, 55)]) # Michael S. Branicky, Jul 10 2022

Crossrefs

Cf. A018900, A187813.

Cf. A226636 (b = 3), A226969 (b = 4), A227062 (b = 5), A227080 (b = 6), A227092 (b = 7), A227095 (b = 8), A227238 (b = 9), A052224 (b = 10).

Sequence in context: A214031 A250293 A058898 * A123840 A258589 A103804

Adjacent sequences: A227089 A227090 A227091 * A227093 A227094 A227095

Keyword

nonn,base

Author

Tom Edgar, Sep 01 2013

Status

approved