A109513 Let k be an m-digit integer. Then k is a Pithy number if the k-th m-tuple in the decimal digits of Pi (after the decimal point) is the string k.

1, 19, 94, 3542, 7295, 318320, 927130, 939240, 688370303, 7682437410, 7996237896, 89594051933

Offset

0,2

Links

Table of n, a(n) for n=0..11.

David G. Andersen, The Pi-Search Page.

Example

1 is a term because the first digit in Pi (after the decimal point) is 1.
19 is a term because the 19th pair of digits (after the decimal point) in Pi is 19:
      1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19
  3. 14 15 92 65 35 89 79 32 38 46 26 43 38 32 79 50 28 84 19 ...

Mathematica

PithyNumbers[m_] := Module[{cc = m(10^m)+m, sol, aa}, sol = Partition[RealDigits[Pi, 10, cc] // First // Rest, m]; Do[aa = FromDigits[sol[[i]]]; If[aa==i, Print[{i, aa}]], {i, Length[sol]}]; ] Example: PithyNumbers[4] produces all 4-digit Pithy numbers

Crossrefs

Cf. A000796, A109514, A057679, A057680.

Sequence in context: A157098 A371532 A037238 * A173368 A041696 A277977

Adjacent sequences: A109510 A109511 A109512 * A109514 A109515 A109516

Keyword

base,more,nonn

Author

Colin Rose, Jul 01 2005

Extensions

a(8)-a(11) from J. Volkmar Schmidt, Dec 17 2023

Status

approved