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A061501 a(1) = 1, a(n+1) = (a(n) + n) mod 10. 3
1, 2, 4, 7, 1, 6, 2, 9, 7, 6, 6, 7, 9, 2, 6, 1, 7, 4, 2, 1, 1, 2, 4, 7, 1, 6, 2, 9, 7, 6, 6, 7, 9, 2, 6, 1, 7, 4, 2, 1, 1, 2, 4, 7, 1, 6, 2, 9, 7, 6, 6, 7, 9, 2, 6, 1, 7, 4, 2, 1, 1, 2, 4, 7, 1, 6, 2, 9, 7, 6, 6, 7, 9, 2, 6, 1, 7, 4, 2, 1, 1, 2, 4, 7, 1, 6, 2, 9, 7, 6, 6, 7, 9, 2, 6, 1, 7, 4, 2, 1, 1, 2, 4, 7, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

First row of array shown below.

a(n) = most significant digit of A062273(n).

Period 20: repeat [1, 2, 4, 7, 1, 6, 2, 9, 7, 6, 6, 7, 9, 2, 6, 1, 7, 4, 2, 1]. - Peter M. Chema, Feb 12 2017

LINKS

Table of n, a(n) for n=1..105.

FORMULA

a(n) = A008954(n-1) + 1.

a(n) = A000124(n) mod 10. - Peter M. Chema, Feb 11 2017

From Chai Wah Wu, Jan 09 2020: (Start)

a(n) = a(n-5) - a(n-10) + a(n-15) for n > 15.

G.f.: x*(-x^14 - 2*x^13 - 4*x^12 - 7*x^11 - x^10 - 5*x^9 - 5*x^7 - 5*x^5 - x^4 - 7*x^3 - 4*x^2 - 2*x - 1)/(x^15 - x^10 + x^5 - 1). (End)

EXAMPLE

1 2 4 7 1 6 2 9 7 6 6 ...

3 5 8 2 7 3 0 8 7 7 ...

6 9 3 8 4 1 9 8 8 ...

0 4 9 5 2 0 9 9 ...

5 0 6 3 1 0 0 ...

1 7 4 2 1 1 ...

MATHEMATICA

a = {1}; Do[AppendTo[a, Mod[a[[n - 1]] + n - 1, 10]], {n, 2, 120}]; a (* Michael De Vlieger, Feb 13 2017 *)

PROG

(PARI) a(n)=if(n==1, return(1)); (a(n-1)+n-1)%10

for(n=1, 50, print1(a(n), ", ")) \\ Derek Orr, Feb 26 2017

CROSSREFS

Cf. A061352, A061353.

Cf. A062273, A077577, A077578.

Cf. A000124.

Sequence in context: A097879 A180658 A019748 * A272001 A089349 A118424

Adjacent sequences:  A061498 A061499 A061500 * A061502 A061503 A061504

KEYWORD

base,nonn,less

AUTHOR

Amarnath Murthy, May 06 2001

EXTENSIONS

Better description and more terms from Larry Reeves (larryr(AT)acm.org), May 08 2001

STATUS

approved

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Last modified October 28 12:48 EDT 2020. Contains 338055 sequences. (Running on oeis4.)