A090635 Trajectory of 63 under the map k -> A003415(k) (taking the arithmetic derivative).

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

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