A061472 First (leftmost) digit - second digit + third digit - fourth digit .... = 3.

3, 30, 41, 52, 63, 74, 85, 96, 102, 113, 124, 135, 146, 157, 168, 179, 201, 212, 223, 234, 245, 256, 267, 278, 289, 300, 311, 322, 333, 344, 355, 366, 377, 388, 399, 410, 421, 432, 443, 454, 465, 476, 487, 498, 520, 531, 542, 553, 564, 575, 586, 597, 630

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

A225693(n) = 3. - Robert Israel, Jun 12 2019

Example

124 is in the sequence since 1 - 2 + 4 = 3.

Maple

A225693:= proc(n) local L, m, i;
  L:= convert(n, base, 10);
  m:= nops(L);
  add(L[i]*(-1)^(m-i), i=1..m);
end proc:
select(A225693=3, [$1..1000]); # Robert Israel, Jun 12 2019

Mathematica

aQ[n_] := Differences[Total @ Take[IntegerDigits[n], {#, -1, 2}] & /@ {2, 1}][[1]] == 3; Select[Range[1000], aQ] (* Amiram Eldar, Jun 12 2019 *)
Select[Range[1000], Total[Times@@@Partition[Riffle[IntegerDigits[#], {1, -1}, {2, -1, 2}], 2]]==3&] (* Harvey P. Dale, May 16 2020 *)

Prog

(PARI) isok(n) = my(d=digits(n)); sum(k=1, #d, (-1)^(k+1)*d[k]) == 3; \\ Michel Marcus, Jun 12 2019

Crossrefs

Cf. A008593, A060978-A060980, A060982, A061470-A061479, A061870-A061882, A225693.

Sequence in context: A169966 A140153 A095045 * A132084 A208880 A012009

Adjacent sequences: A061469 A061470 A061471 * A061473 A061474 A061475

Keyword

nonn,base,easy

Author

Amarnath Murthy, May 05 2001

Extensions

More terms from Robert G. Wilson v, May 10 2001 and from Larry Reeves (larryr(AT)acm.org), May 14 2001

Status

approved