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 1-5 of 5 results.

A138818 Concatenation of initial digit of n-th even superperfect number A061652(n), initial digit of n-th Mersenne prime A000668(n) and initial digit of n-th perfect number A000396(n).

Original entry on oeis.org

236, 472, 134, 618, 483, 618, 251, 122, 122, 361, 811, 811
Offset: 1

Views

Author

Omar E. Pol, Apr 05 2008

Keywords

Comments

Also, concatenation of initial digit of n-th superperfect number A019279(n), initial digit of n-th Mersenne prime A000668(n) and initial digit of n-th perfect number A000396(n), if there are no odd superperfect numbers.
Also, concatenation of A138124(n), A135613(n) and A135617(n).

Links

Crossrefs

Cf. A000396, A000668, A019279, A061652, A135613, A135617, A138124, A138816, A138817, A138819, A138841, A138842, A138843.

A138820 Concatenation of n-th even superperfect number, n-th Mersenne prime A000668(n) and n-th perfect number.

Original entry on oeis.org

236, 4728, 1631496, 641278128, 4096819133550336, 655361310718589869056, 262144524287137438691328, 107374182421474836472305843008139952128, 115292150460684697623058430092136939512658455991569831744654692615953842176
Offset: 1

Views

Author

Omar E. Pol, Apr 05 2008

Keywords

Comments

Concatenation of A061652(n), A000668(n) and A000396(n).
Also concatenation of n-th superperfect number, n-th Mersenne prime A000668(n) and n-th perfect number, if there are no odd superperfect numbers.

Crossrefs

Cf. A000396, A000668, A019279, A061652, A138818, A138819.

A138833 Concatenation of n-th perfect number and n-th Mersenne prime A000668(n).

Original entry on oeis.org

63, 287, 49631, 8128127, 335503368191, 8589869056131071, 137438691328524287, 23058430081399521282147483647, 26584559915698317446546926159538421762305843009213693951, 191561942608236107294793378084303638130997321548169216618970019642690137449562111
Offset: 1

Views

Author

Omar E. Pol, Apr 06 2008

Keywords

Comments

a(15) has 1156 digits. - Harvey P. Dale, Jan 10 2023

Examples

			a(3)=49631 because A000396(3)=496 and A000668(3)=31.

Links

Crossrefs

Cf. A000396, A000668, A138816, A138817, A138818, A138819, A138820, A138821, A138822, A138832.

Programs

  • Mathematica
    Module[{nn=10},FromDigits[Flatten[IntegerDigits/@#]]&/@Thread[{PerfectNumber[ Range[ nn]],2^ MersennePrimeExponent[ Range[nn]]-1}]] (* Harvey P. Dale, Jan 10 2023 *)

Extensions

Corrected and extended by Harvey P. Dale, Jan 10 2023

A138832 Concatenation of n-th Mersenne prime A000668(n) and n-th perfect number.

Original entry on oeis.org

36, 728, 31496, 1278128, 819133550336, 1310718589869056, 524287137438691328, 21474836472305843008139952128, 23058430092136939512658455991569831744654692615953842176
Offset: 1

Views

Author

Omar E. Pol, Apr 06 2008

Keywords

Examples

			a(3)=31496 because A000668(3)=31 and A000396(3)=496.

Crossrefs

Cf. A000396, A000668, A138816, A138817, A138818, A138819, A138820, A138821, A138822, A138833.

A138728 Array read by rows: row n lists n-th even superperfect number A061652(n), n-th Mersenne prime A000668(n) and n-th perfect number A000396(n).

Original entry on oeis.org

2, 3, 6, 4, 7, 28, 16, 31, 496, 64, 127, 8128, 4096, 8191, 33550336, 65536, 131071, 8589869056, 262144, 524287, 137438691328, 1073741824, 2147483647, 2305843008139952128, 1152921504606846976, 2305843009213693951
Offset: 1

Views

Author

Omar E. Pol, Apr 07 2008

Keywords

Examples

			Array begins:
2, 3, 6
4, 7, 28
16, 31, 496

Links

Crossrefs

Cf. A000396, A000668, A019279, A061652, A138818, A138819.
Showing 1-5 of 5 results.

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

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