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.

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A352317 Numbers m such that A352688(m) = 1.

Original entry on oeis.org

3, 9, 10, 12, 18, 19, 21, 27, 28, 30, 36, 37, 39, 45, 46, 48, 54, 55, 57, 63, 64, 66, 72, 73, 75, 81, 82, 84, 90, 91, 93, 99, 100, 102, 108, 109, 111, 117, 118, 120, 126, 127, 129, 135, 136, 138, 144, 145, 147, 153, 154, 156, 162, 163, 165, 171, 172, 174, 180, 181, 183, 189, 190, 192, 198, 199
Offset: 1

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Author

Bernard Schott, Apr 14 2022

Keywords

Comments

Equivalently: numbers m such that the sum of digits (A007953) of the integers from 1 to A331786(m) is not divisible by m.
Numbers m such that the first run of A331786(m) consecutive numbers whose sum of digits (A007953) is not divisible by m begins at 1.
A331786(m) is the largest possible number of consecutive integers whose sum of digits is not divisible by m.
For this sequence here, A352689(m) = A331786(m).

Examples

			For m = 10, the sum of digits of the integers from 1 up to A331786(10) = 18 is not divisible by 10; then for 19, sod(19) = 10 is divisible by 10, hence 10 is a term.
		

Crossrefs

A008591 \ {0} and A017173 \ {1} are subsequences.

Programs

  • PARI
    a88(n) = my(t=gcd(n%9, 9)); if(t<9, 10^lift(Mod(-1, n/t)/(9/t)) - 10^(n\9)*(n%9-t+1) + 1, 1); \\ A352688
    isok(m) = a88(m) == 1; \\ Michel Marcus, Apr 15 2022

Extensions

More terms from Michel Marcus, Apr 15 2022

A352689 a(n) is the last term of the first run of A331786(n) consecutive numbers whose sum of digits (A007953) is not divisible by n.

Original entry on oeis.org

10, 2, 1002, 13, 14, 1005, 10000006, 8, 18, 1000018, 38, 10000000038, 1048, 1058, 10000068, 1000000000000078, 98, 198, 100000000198, 398, 100000000000000398, 100498, 100598, 100000000698, 100000000000000000000798, 998, 1998, 10000000000001998, 3998, 1000000000000000000003998
Offset: 2

Views

Author

Bernard Schott, Mar 28 2022

Keywords

Comments

A331786(n) is the number of consecutive integers in the largest such possible run.

Examples

			a(4) = 1002 because the A331786(4) = 6 consecutive numbers 997, 998, 999, 1000, 1001, 1002 have respectively sum of digits = 25, 26, 27, 1, 2, 3 and none is divisible by 4, and there is no smaller m < 1002 such that sum of digits of m-5, m-4, m-3, m2, m-1, m is not divisible by 4.
		

Crossrefs

Formula

a(n) = A352688(n) + A331786(n) - 1.

Extensions

More terms from Jinyuan Wang, Mar 28 2022
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