A352438 Numbers k whose decimal expansion starts with the sum of the last two digits of k.

10, 20, 30, 40, 50, 60, 70, 80, 90, 101, 110, 202, 211, 220, 303, 312, 321, 330, 404, 413, 422, 431, 440, 505, 514, 523, 532, 541, 550, 606, 615, 624, 633, 642, 651, 660, 707, 716, 725, 734, 743, 752, 761, 770, 808, 817, 826, 835, 844, 853, 862, 871, 880, 909, 918, 927, 936, 945, 954, 963, 972, 981, 990, 1001

Offset

1,1

Links

Table of n, a(n) for n=1..64.

Example

    10 is a term because   "10" starts with  "1" = 1 + 0;
   101 is a term because  "101" starts with  "1" = 0 + 1;
  1019 is a term because "1019" starts with "10" = 1 + 9; etc.

Mathematica

q[n_] := Module[{d = IntegerDigits[n], s, ds, nds}, s = Plus @@ d[[-2 ;; -1]]; ds = IntegerDigits[s]; nds = Length[ds]; ds == d[[1 ;; nds]]]; Select[Range[10, 1001], q] (* Amiram Eldar, Mar 16 2022 *)

Prog

(Python)
def ok(n):
    s = str(n)
    return n > 9 and s.startswith(str(int(s[-2])+int(s[-1])))
print([k for k in range(1002) if ok(k)]) # Michael S. Branicky, Mar 16 2022

Crossrefs

Cf. A352439.

Sequence in context: A273239 A343452 A043489 * A028440 A332046 A166511

Adjacent sequences: A352435 A352436 A352437 * A352439 A352440 A352441

Keyword

base,nonn

Author

Eric Angelini and Carole Dubois, Mar 16 2022

Status

approved