A119791 -id:A119791

Search: a119791 -id:a119791

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A119792

Record values in A119791.

+20
2

1, 2, 4, 5, 6, 8, 12, 15, 18, 20, 24, 30, 32, 40, 48, 60, 63, 64, 80, 84, 90, 96, 120, 160, 180, 240, 252, 256, 288, 320, 336, 384, 432, 512

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

a(n)=A119791(A119793(n)) and A119791(m)<a(n) for m < A119793(n).

LINKS

Table of n, a(n) for n=1..34.

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 24 2006

STATUS

approved

A119793

Where record values of A119791 occur.

+20
2

1, 2, 3, 4, 6, 7, 10, 12, 21, 28, 30, 40, 77, 105, 175, 210, 400, 462, 495, 560, 990, 1275, 1540, 3213, 7140, 10626, 15400, 27456, 32725, 49896, 58905, 77616, 144144, 248976

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

A119792(n)=A119791(a(n)) and A119791(m) < A119792(n) for m<a(n).

LINKS

Table of n, a(n) for n=1..34.

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, May 24 2006

STATUS

approved

A180709

a(n) = sigma(n*a(n-1)) for n>1 with a(1)=1.

+10
0

1, 3, 13, 98, 1026, 16940, 318402, 8751951, 138772480, 4323245864, 120795955200, 5325759445800, 253615827548160, 17175333492928512, 1074413211620474880, 76931332113306746880, 5820049307236627906560, 433263727052606574415872

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..18.

MATHEMATICA

nxt[{n_, a_}]:={n+1, DivisorSigma[1, a(n+1)]}; NestList[nxt, {1, 1}, 20][[All, 2]] (* Harvey P. Dale, Apr 28 2018 *)

PROG

(PARI) a(n)=if(n==1, 1, sigma(n*a(n-1)))

CROSSREFS

Cf. A119791.

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Sep 18 2010

STATUS

approved

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