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.

A077730 a(n) = A077729(n)^(1/2).

Original entry on oeis.org

1, 15, 1825, 6667, 235702, 2581988, 8819171, 94280904, 316227766, 10050378152592120755, 1054092553389459777333, 348155311911395676354583, 36237153766973933397363154, 3760507165451774726100982411
Offset: 1

Views

Author

Amarnath Murthy, Nov 19 2002

Keywords

Crossrefs

Cf. A077729.

Extensions

Corrected and extended by Sascha Kurz, Jan 04 2003

A138173 a(n) is the smallest m such that m^3 begins with n^2.

Original entry on oeis.org

1, 16, 21, 55, 63, 154, 17, 4, 201, 10, 23, 113, 257, 27, 609, 295, 307, 148, 1535, 342, 164, 1692, 809, 1793, 397, 878, 9, 428, 944, 4482, 987, 1008, 1029, 4872, 107, 2349, 5154, 5247, 2478, 252, 552, 5609, 5697, 5785, 2726, 1284, 2806, 6131, 2885
Offset: 1

Views

Author

Zak Seidov, Mar 05 2008

Keywords

Comments

Differs from A030691.

Links

Crossrefs

Cf. A030690, A030691, A018852, A018797, A077729, A077730, A138174.

Programs

  • Python
    from gmpy2 import iroot
def A138173(n):
    d, nd = 1, n**2
    while True:
        x = iroot(nd-1,3)[0]+1
        if x**3 < nd+d:
            return int(x)
        d *= 10
        nd *= 10 # Chai Wah Wu, May 24 2016
  • Sage
    A138173 = lambda n: next(m for m in IntegerRange(1, infinity) if str(m**3).startswith(str(n**2)))
# D. S. McNeil, Dec 12 2010

Formula

a(n) = (A138174(n))^(1/3).

A138174 a(n) is the smallest cube that begins with n^2.

Original entry on oeis.org

1, 4096, 9261, 166375, 250047, 3652264, 4913, 64, 8120601, 1000, 12167, 1442897, 16974593, 19683, 225866529, 25672375, 28934443, 3241792, 3616805375, 40001688, 4410944, 4843965888, 529475129, 5764224257, 62570773, 676836152
Offset: 1

Views

Author

Zak Seidov, Mar 05 2008

Keywords

Comments

Differs from A030690.

Crossrefs

Cf. A030690, A030691, A018852, A018797, A077729, A077730, A138173.

Formula

a(n) = (A138173(n))^3.

Extensions

Corrected by D. S. McNeil, Dec 12 2010
Showing 1-3 of 3 results.

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

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