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A090635 Trajectory of 63 under the map k -> A003415(k) (taking the arithmetic derivative). 4
63, 51, 20, 24, 44, 48, 112, 240, 608, 1552, 3120, 8144, 16304, 32624, 65264, 130544, 264928, 678448, 1356912, 4979232, 19424016, 58272480, 226593936, 763164288, 3467499840, 16339520448, 65370077568, 295266178368, 1223245608192, 6931725175296, 40582548986112 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

A. M. Gleason et al., The William Lowell Putnam Mathematical Competition: Problems and Solutions 1938-1964, Math. Assoc. America, 1980, p. 295.

LINKS

Table of n, a(n) for n=1..31.

FORMULA

a(n+1) = A003415(a(n)), a(1) = 63. a(n) = 4*A129286(n-3) for n > 2. - M. F. Hasler, Nov 27 2019

PROG

(PARI) A090635(n, a=63)={if(n<0, vector(-n, n, if(n>1, a=A003415(a), a)), for(n=2, n, a=A003415(a)); a)}  \\ For n<0 return the vector a[1..-n]. - M. F. Hasler, Nov 27 2019

CROSSREFS

Cf. A003415, A090636, A090637.

Sequence in context: A202157 A145585 A033383 * A278825 A086859 A278827

Adjacent sequences:  A090632 A090633 A090634 * A090636 A090637 A090638

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 14 2003

EXTENSIONS

More explicit name from M. F. Hasler, Nov 27 2019

STATUS

approved

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Last modified June 27 13:50 EDT 2022. Contains 354896 sequences. (Running on oeis4.)