cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A035076 a(n) is root of square starting with digit 9: first term of runs.

Original entry on oeis.org

30, 95, 300, 949, 3000, 9487, 30000, 94869, 300000, 948684, 3000000, 9486833, 30000000, 94868330, 300000000, 948683299, 3000000000, 9486832981, 30000000000, 94868329806, 300000000000, 948683298051, 3000000000000
Offset: 2

Views

Author

Patrick De Geest, Nov 15 1998

Keywords

Crossrefs

Cf. A067479 (squares), A017936.
Cf. 2: A035069, 3: A035070, 4: A035071, 5: A035072, 6: A035073, 7: A035074, 8: A035075.

Programs

  • Mathematica
    Ceiling[Sqrt[9*10^Range[2,30]]] (* Harvey P. Dale, Aug 07 2013 *)

Formula

a(n) = ceiling(sqrt(9*10^n)), n > 1.

A035075 a(n) = ceiling(sqrt(8*10^n)).

Original entry on oeis.org

9, 29, 90, 283, 895, 2829, 8945, 28285, 89443, 282843, 894428, 2828428, 8944272, 28284272, 89442720, 282842713, 894427191, 2828427125, 8944271910, 28284271248, 89442719100, 282842712475, 894427191000, 2828427124747
Offset: 1

Views

Author

Patrick De Geest, Nov 15 1998

Keywords

Comments

Also, first term of runs of consecutive numbers whose square starts with the digit 8.

Crossrefs

Cf. A067478 (squares), A035069-A035076 (2..9), A045862.

Programs

  • Mathematica
    Ceiling[Sqrt[8*10^Range[30]]] (* Harvey P. Dale, Apr 12 2013 *)
  • Python
    from math import isqrt
    def a(n): return isqrt(8*10**n) + 1
    print([a(n) for n in range(1, 25)]) # Michael S. Branicky, Sep 29 2021

Formula

a(n) = ceiling(sqrt(8*10^n)), n > 0.

A067472 Smallest n-digit square starting with 2.

Original entry on oeis.org

25, 225, 2025, 20164, 200704, 2002225, 20007729, 200024449, 2000057284, 20000182084, 200000361796, 2000001237796, 20000000402496, 200000010642496, 2000000040249600, 20000000215721449, 200000000447251216
Offset: 2

Views

Author

Amarnath Murthy, Feb 09 2002

Keywords

Crossrefs

Cf. A035069 (roots), A045785, A067479 (2..9).

Programs

  • Mathematica
    Table[Ceiling[Sqrt[2*10^(n-1)]]^2,{n,2,30}] (* Harvey P. Dale, Apr 18 2021 *)
  • PARI
    for(n=2,25,a=ceil(sqrt(2*10^(n-1)))^2; print(a))

Formula

a(n) = ceiling(sqrt(2*10^(n-1)))^2, n>1. - Rick L. Shepherd, Feb 14 2002

Extensions

More terms from Rick L. Shepherd, Feb 14 2002
Showing 1-3 of 3 results.