keyword:dumb - cp's OEIS frontend

A039928 Sum of first n terms of A_n (using absolute values of terms).

0, 3, 3, 0, 10, 12, 1, 24, 25, 32, 116, 12, 412, 109, 126, 2389, 12497, 28772, 126, 72795, 247786, 770213, 159378001963452599318, 2169128, 442, 311, 378, 789, 10015050, 75, 74253544, 7881195, 2461717833658872781238383813854943728, 51, 17, 824, 855, 2, 29981, 3087, 215308, 123456790123456790123456790123456790123452, 132813776, 1086162642, 1836311902, 400276874544

Offset: 1

Russ Cox

Since the sequences in the OEIS occasionally change their initial terms (for editorial reasons), this is an especially ill-defined sequence! - N. J. A. Sloane, Jan 01 2005

The next term, a(47), is currently unknown. - Jianing Song, Oct 07 2018

			A000001 (Number of groups of order n) begins 0,... -> a(1) = 0
A000002 (Kolakoski sequence) begins 1, 2,... -> a(2) = 3
A000003 begins 1, 1, 1,... -> a(3) = 3
A000004 (The zero sequence) begins 0, 0, 0, 0,... -> a(4) = 0
A000005 (The number of divisors) begins 1, 2, 2, 3, 2, ... -> a(5) = 10
...
A000010 (Euler totient function) begins 1, 1, 2, 2, 4, 2, 6, 4, 6, ... so a(10) = 1 + 1 + 2 + 2 + 4 + 2 + 6 + 4 + 6 + 4 = 32.

Index entries for sequences whose definition involves A_n (or An).

Cf. A031135, A031214, A100543 (uses signed values).

Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 27 2004

a(1) changed from 1 to 0 and extended by Jianing Song, Oct 06 2018

A048659 Positions of letters in English alphabet (U.S. pronunciation) that rhyme with 'e'.

Original entry on oeis.org

2, 3, 4, 5, 7, 16, 20, 22, 26

Offset: 1

Andrew Coker (andrewc(AT)atu.com.au)

			a(1) = 2 because the first letter that rhymes with 'e' is 'b'.

A061727 A000217 interleaved with A061726.

Original entry on oeis.org

1, 4, 3, 12, 6, 30, 10, 50, 15, 60, 21, 84, 28, 140, 36, 180, 45, 180, 55, 220, 66, 330, 78, 390, 91, 364, 105, 420, 120, 600, 136, 680, 153, 612, 171, 684, 190, 950, 210, 1050, 231, 924, 253, 1012, 276, 1380, 300, 1500, 325, 1300, 351, 1404, 378, 1890, 406

Offset: 1

Jason Earls, May 05 2001

Norman Sullivan, Test Your Own IQ, Workman Publishing Co. New York, NY, 1994, pp. 48, 50.

Harry J. Smith, Table of n, a(n) for n = 1..2000

Cf. A000217, A061726.

Array[{#, (4 + Boole[EvenQ@ #]) #} &@ PolygonalNumber@ # &, 28] // Flatten (* Michael De Vlieger, Jul 01 2018 *)

{ f="b061727.txt"; for (n=1, 1000, a=n*(n + 1)/2; if (a%2, t=a*4, t=a*5); write(f, 2*n - 1, " ", a); write(f, 2*n, " ", t) ) } \\ Harry J. Smith, Jul 27 2009

More terms from David Wasserman, Jun 25 2002

A066555 a(n) = next substring in concatenation of even numbers with length n (incl. leading zeros).

Original entry on oeis.org

2, 46, 810, 1214, 16182, 22242, 6283032, 34363840, 424446485, 525456586, 6264666870, 727476788082, 8486889092949, 69810010210410, 610811011211411, 6118120122124126, 12813013213413613, 814014214414614815

Offset: 1

Amarnath Murthy, Dec 17 2001

			a(1)..a(5) = 246810121416182, a(6) = 022242 (leading zero not shown).

Cf. A066553.

Edited by Frank Ellermann, Feb 04 2002

A104175 From the words to the song "867-5309/Jenny" by Tommy Tutone.

Original entry on oeis.org

8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9, 8, 6, 7, 5, 3, 0, 9

Offset: 1

Jonathan Garth Flittner (flittnerj(AT)wlu.edu), Mar 10 2005

			Jenny, Jenny who can I turn to?
You give me something I can hold on to.
I know you'll think I'm like the others before
Who saw your name and number on the wall.
Jenny I've got your number
I need to make you mine
Jenny don't change your number
8 6 7 - 5 3 0 9  (8 6 7 - 5 3 0 9)
8 6 7 - 5 3 0 9  (8 6 7 - 5 3 0 9)
...

Brad DeLong, Jenny (867-5309)
lyrics.com, 867-5309/Jenny.
Wikipedia, 867-5309/Jenny.
Index entries for sequences related to songs

Cf. A182369.

ContinuedFraction[(176189+Sqrt[32325522853])/38946,84]-1 (* Adam P. Goucher, Apr 27 2014 *)

def a(n): return [8, 6, 7, 5, 3, 0, 9][(n-1)%7]
print([a(n) for n in range(1, 85)]) # Michael S. Branicky, Aug 06 2021

G.f.: (8 + 6*x + 7*x^2 + 5*x^3 + 3*x^4 + 9*x^6)/(1 - x^7). - Adam P. Goucher, Apr 27 2014

Name corrected by Michael S. Branicky, Aug 06 2021

A105328 Digital expansion of e*Pi: numbers from each pair of successive digits.

Original entry on oeis.org

85, 39, 73, 42, 22, 67, 35, 67, 6, 54, 63, 55, 8, 69, 54, 65, 74, 49, 50, 34, 88, 85, 35, 76, 51, 14, 96, 18, 79, 60, 11, 30, 17, 92, 28, 61, 11, 57, 33, 8, 7, 57, 25, 63, 86, 97, 10, 47, 39, 43, 91, 37, 74, 94, 25, 11, 67, 74, 67, 64, 63, 21, 18, 75, 90, 69, 60, 23, 99, 6, 18, 36

Offset: 1

Zak Seidov, Apr 30 2005

Table[FromDigits[Partition[RealDigits[N[e*Pi, 200]][[1]], 2][[i]]], {i, 100}]

A107626 Numbers n such that every digit of both n and n^2 contains a loop (only digits 0,4,6,8,9 in n and n^2).

Original entry on oeis.org

8, 64, 80, 98, 640, 664, 800, 898, 980, 998, 6400, 6640, 6664, 8000, 8980, 8998, 9800, 9980, 9998, 64000, 66400, 66640, 66664, 80000, 89800, 89980, 89998, 98000, 98998, 99800, 99980, 99998, 640000, 664000, 664064, 666400, 666640, 666664, 684908, 800000, 806008

Offset: 1

Zak Seidov, May 18 2005

Corresponding squares in A107627. Cf. A001744 Every digit contains a loop.

Cf. A001744, A107624, A107625, A107627.

Do[id=Union[IntegerDigits[n^2], IntegerDigits[n]];If[Count[id, 1]+Count[id, 2]+Count[id, 3]+Count[id, 5]+Count[id, 7]==0, Print[n]], {n, 10000}]

is_a001744(n) = #setintersect(vecsort(digits(n), , 8), [1, 2, 3, 5, 7])==0
is(n) = is_a001744(n) && is_a001744(n^2) \\ Felix Fröhlich, Sep 09 2019

More terms from Felix Fröhlich, Sep 09 2019

A107627 Numbers n such that every digit of n and sqrt(n) contains a loop (only digits 0,4,6,8,9 in n and sqrt(n)).

Original entry on oeis.org

64, 4096, 6400, 9604, 409600, 440896, 640000, 806404, 960400, 996004, 40960000, 44089600, 44408896, 64000000, 80640400, 80964004, 96040000, 99600400, 99960004

Offset: 1

Zak Seidov, May 18 2005

Corresponding square roots in A107626. Cf. A001744 Every digit contains a loop.

Harvey P. Dale, Table of n, a(n) for n = 1..100

Cf. A001744, A107624, A107625, A107626.

Do[id=Union[IntegerDigits[n^2], IntegerDigits[n]];If[Count[id, 1]+Count[id, 2]+Count[id, 3]+Count[id, 5]+Count[id, 7]==0, Print[n^2]], {n, 10000}]
With[{c={0,4,6,8,9}},#^2&/@Select[FromDigits/@Tuples[c,4],SubsetQ[c,IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Oct 01 2023 *)

A114804 The numbers 3^n-1 written in groups of three digits, with leading zeros omitted.

Original entry on oeis.org

282, 680, 242, 728, 218, 665, 601, 968, 259, 48, 177, 146, 531, 440, 159, 432, 247, 829, 681, 434, 890, 643, 46, 720, 129, 140, 162, 387, 420, 488, 116, 226, 146, 634, 867, 844, 1, 46, 35, 320, 231, 381, 59, 608, 941, 431, 788, 262, 824, 295, 364, 808

Offset: 1

Jonathan Vos Post, Feb 18 2006

			2, 8, 26, 80, 242, 728, 2186, ...

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Cf. A024023, A114645, A114807, A114808.

FromDigits/@Partition[Flatten[IntegerDigits/@(3^Range[30]-1)],3] (* Harvey P. Dale, Jul 04 2021 *)

Terms recomputed to use the definition equivalent to A114645. - R. J. Mathar, Jun 23 2014

A114807 The numbers 4^n-1 written in groups of three digits, with leading zeros omitted.

Original entry on oeis.org

315, 632, 551, 23, 409, 516, 383, 655, 352, 621, 431, 48, 575, 419, 430, 316, 777, 215, 671, 88, 632, 684, 354, 551, 73, 741, 823, 429, 496, 729, 517, 179, 869, 183, 687, 194, 767, 352, 748, 779, 69, 431, 99, 511, 627, 775, 439, 804, 651, 110, 317, 592, 186, 44

Offset: 1

Jonathan Vos Post, Feb 19 2006

			3, 15, 63, 255, 1023, 4095, 16383, ...

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A114645, A114804, A114808, A114827.

FromDigits[#] & /@ Partition[ Flatten@ IntegerDigits@ Table[4^n - 1, {n, 22}], 3] (* Robert G. Wilson v, Jun 23 2014 *)
FromDigits/@Partition[Flatten[IntegerDigits/@(4^Range[30]-1)],3] (* Harvey P. Dale, Jun 03 2025 *)

from itertools import count, islice
def bgen(): yield from (d for n in count(1) for d in str((1 << 2*n)-1))
def agen(): g = bgen(); yield from (int("".join(t)) for t in zip(g, g, g))
print(list(islice(agen(), 54))) # Michael S. Branicky, Dec 25 2022

a(4) and following changed by Georg Fischer, Dec 25 2022

cp's OEIS Frontend

A039928 Sum of first n terms of A_n (using absolute values of terms).

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Extensions

A048659 Positions of letters in English alphabet (U.S. pronunciation) that rhyme with 'e'.

Views

Author

Keywords

Examples

A061727 A000217 interleaved with A061726.

Views

Author

Keywords

References

Links

Crossrefs

Programs

Mathematica

PARI

Extensions

A066555 a(n) = next substring in concatenation of even numbers with length n (incl. leading zeros).

Views

Author

Keywords

Examples

Crossrefs

Extensions

A104175 From the words to the song "867-5309/Jenny" by Tommy Tutone.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

Mathematica

Python

Formula

Extensions

A105328 Digital expansion of e*Pi: numbers from each pair of successive digits.

Views

Author

Keywords

Programs

Mathematica

A107626 Numbers n such that every digit of both n and n^2 contains a loop (only digits 0,4,6,8,9 in n and n^2).

Views

Author

Keywords

Comments

Crossrefs

Programs

Mathematica

PARI

Extensions

A107627 Numbers n such that every digit of n and sqrt(n) contains a loop (only digits 0,4,6,8,9 in n and sqrt(n)).

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

Mathematica

A114804 The numbers 3^n-1 written in groups of three digits, with leading zeros omitted.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

Mathematica

Extensions