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.

Previous Showing 11-16 of 16 results.

A277397 Like 4-white numbers but with blocks of 4 starting at left.

Original entry on oeis.org

0, 1, 1000, 11110, 14638, 15628, 17170, 18217, 19305, 19999, 21649, 22320, 25234, 29041, 30195, 31428
Offset: 1

Views

Author

Paolo P. Lava, Oct 13 2016

Keywords

Examples

			14638^4 = 45912080296849936 and 4591 + 2080+ 2968 + 4993 + 6 = 14638.

Crossrefs

Cf. A037042-A037045, A274833, A274834, A277398-A277400.

Programs

  • Maple
    P:=proc(q,h) local a,b,c,d,n; print(0); for n from 1 to q do
a:=n^h; d:=ilog10(n^h)+1; c:=d-h*trunc(d/h); b:=0;
while a>0 do b:=b+(a mod 10^c); a:=trunc(a/10^c); c:=h; od;
if n=b then print(n); fi; od; end: P(10^15,4);

A277398 Like 5-white numbers but with blocks of 5 starting at left.

Original entry on oeis.org

1, 10000, 73440, 95120, 218510, 221220, 222220, 242900, 245610, 289970, 344070
Offset: 1

Views

Author

Paolo P. Lava, Oct 13 2016

Keywords

Examples

			73440^5 = 2136305413264402022400000 and 21363 + 05413 + 26440 + 20224 + 00000 = 73440.

Crossrefs

Cf. A037042-A037045, A274833, A274834, A277397, A277399, A277400.

Programs

  • Maple
    P:=proc(q,h) local a,b,c,d,n; print(0); for n from 1 to q do
a:=n^h; d:=ilog10(n^h)+1; c:=d-h*trunc(d/h); b:=0;
while a>0 do b:=b+(a mod 10^c); a:=trunc(a/10^c); c:=h; od;
if n=b then print(n); fi; od; end: P(10^15,5);

A277400 Like 7-white numbers but with blocks of 7 starting at left.

Original entry on oeis.org

0, 1, 1000000, 20585070, 25104356, 25975583, 27483737, 27940490, 27941490, 28133416, 29069509, 32345773, 32482961, 32581773, 33332330, 34310934, 34676272, 35530163, 35707886, 36067139, 41716867, 42163087, 42568703, 44444440, 47745130
Offset: 1

Views

Author

Paolo P. Lava, Oct 13 2016

Keywords

Examples

			20585070^7 = 1566269305839650871270449961448347855098390430000000 and 1566269 + 3058396 + 5087127 + 0449961 + 4483478 + 5509839 + 0430000 + 000 = 20585070.

Crossrefs

Cf. A037042-A037045, A274833, A274834, A277397, A277398, A277399.

Programs

  • Maple
    P:=proc(q,h) local a,b,c,d,n; print(0); for n from 1 to q do
a:=n^h; d:=ilog10(n^h)+1; c:=d-h*trunc(d/h); b:=0;
while a>0 do b:=b+(a mod 10^c); a:=trunc(a/10^c); c:=h; od;
if n=b then print(n); fi; od; end: P(10^15,7);

A277399 Like 6-white numbers but with blocks of 6 starting at left.

Original entry on oeis.org

0, 1, 100000, 1705330, 1818180, 1941030, 2046807, 2227770, 2285010, 2414880, 2598400, 2694600, 2727270, 2728270, 2758239, 2760940, 2857140, 2890810, 2979315, 3040660, 3085911, 3317050, 3541014, 3636460, 4543174
Offset: 1

Views

Author

Paolo P. Lava, Oct 13 2016

Keywords

Examples

			1705330^6 = 24595213291709423201966052256969000000 and 245952 + 132917 + 094232 + 019660 + 522569 + 690000 + 00 = 1705330.

Crossrefs

Cf. A037042-A037045, A274833, A274834, A277397, A277398, A277400.

Programs

  • Maple
    P:=proc(q,h) local a,b,c,d,n; print(0); for n from 1 to q do
a:=n^h; d:=ilog10(n^h)+1; c:=d-h*trunc(d/h); b:=0;
while a>0 do b:=b+(a mod 10^c); a:=trunc(a/10^c); c:=h; od;
if n=b then print(n); fi; od; end: P(10^15,7);
  • Mathematica
    Select[Range[0,4544000],Total[FromDigits/@Partition[IntegerDigits[#^6],UpTo[6]]]==#&] (* Harvey P. Dale, Dec 25 2023 *)

A051534 Integers n for which ceiling(n/2)*10^n - ceiling(n/2) is an n-White number.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 20, 21, 23, 25, 26, 27, 29, 30, 31, 33, 35, 37, 39, 40, 41, 43, 45, 47, 48, 49, 51, 53, 55, 57, 59, 60, 61, 63, 64, 65, 67, 69, 71, 73, 75, 77, 79, 80, 81, 83, 85, 86, 87, 89, 90, 91, 93, 95, 97, 99, 100, 103, 111, 115, 119
Offset: 1

Views

Author

James Sellers

Keywords

Comments

Note that every 1- and 2-digit odd integer appears in the sequence.

Examples

			The number 6 * 10^11 - 6 = 599999999994 is an 11-White number, so the number 11 appears in the sequence.

Crossrefs

Cf. A037042, A037043, A037044, A037045.

A308408 a(n) is the smallest k that is equal to the sum of the digits of k*(k+1)*...*(k+n-1) in base 10^n, or -1 if such a number does not exist.

Original entry on oeis.org

1, 33, -1, 10692, 74016, 1153845, 19999998, 373722624, 3025660311, 39999999996, -1
Offset: 1

Views

Author

Paolo P. Lava, May 25 2019

Keywords

Comments

Partition the product of n consecutive integers, from k to k+n-1, into blocks of n digits starting from right. Sequence lists, for each n, the first number k of the least product whose sum of blocks is equal to k, or -1 if such a number does not exist.
a(12) <= 6*10^12 - 6, a(13) <= 4*10^13 - 4, a(14) <= 6*10^14 - 6, a(15) <= 8*10^15 - 8, a(16) <= 6*10^16 - 6, a(17) <= 8*10^17 - 8, a(18) <= 8*10^18 - 8. - Giovanni Resta, May 25 2019

Examples

			a(2) = 33 because 33*34 = 1122 and 11 + 22 = 33.
a(4) = 10692 because 10692*10693*10694*10695 = 13076137707585480 and 5480 + 758 + 1377 + 3076 + 1 = 10692.

Crossrefs

Cf. A037042, A037043, A037044, A037045, A274833, A274834.

Programs

  • Maple
    P:=proc(q) local a, b,c,j,k,n,x; c:=1; for n from 1 to q do x:=0:
for k from c to q do a:=mul(j,j=k..k+n-1); b:=0; while a>0 do
b:=b+(a mod 10^n); a:=trunc(a/10^n); od; if k>b then x:=x+1;
else if k

Extensions

a(8)-a(11) from Giovanni Resta, May 25 2019
Previous Showing 11-16 of 16 results.

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