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 1-2 of 2 results.

A045792 Squares with initial digit '8'.

Original entry on oeis.org

81, 841, 8100, 8281, 8464, 8649, 8836, 80089, 80656, 81225, 81796, 82369, 82944, 83521, 84100, 84681, 85264, 85849, 86436, 87025, 87616, 88209, 88804, 89401, 801025, 802816, 804609, 806404, 808201, 810000, 811801, 813604, 815409, 817216
Offset: 1

Views

Author

Jeff Burch

Keywords

Crossrefs

Cf. A045862.
Cf. A045784, A045785, A045786, A045787, A045788, A045789, A045791, A045793.

Formula

a(n) = A045862(n)^2. - Michel Marcus, Sep 04 2021

Extensions

a(16) corrected by Sean A. Irvine, Mar 21 2021
Offset 1 from Michel Marcus, Mar 22 2021

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.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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